replace uses of iteritems with six.iteritems

9 years ago · fbe766ad46
parent 7978747198
commit fbe766ad46
16 changed files with 144 additions and 112 deletions
--- a/src/python/grpcio/grpc/framework/alpha/_face_utilities.py
+++ b/src/python/grpcio/grpc/framework/alpha/_face_utilities.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -30,6 +30,8 @@
 import abc
 import collections

+import six
+
 # face_interfaces is referenced from specification in this module.
 from grpc.framework.common import cardinality
 from grpc.framework.face import interfaces as face_interfaces  # pylint: disable=unused-import
@ -111,7 +113,7 @@ def break_down_invocation(service_name, method_descriptions):
  face_cardinalities = {}
  request_serializers = {}
  response_deserializers = {}
-  for name, method_description in method_descriptions.iteritems():
+  for name, method_description in six.iteritems(method_descriptions):
    qualified_name = _qualified_name(service_name, name)
    method_cardinality = method_description.cardinality()
    cardinalities[name] = method_description.cardinality()
@ -139,7 +141,7 @@ def break_down_service(service_name, method_descriptions):
  implementations = {}
  request_deserializers = {}
  response_serializers = {}
-  for name, method_description in method_descriptions.iteritems():
+  for name, method_description in six.iteritems(method_descriptions):
    qualified_name = _qualified_name(service_name, name)
    method_cardinality = method_description.cardinality()
    if method_cardinality is interfaces.Cardinality.UNARY_UNARY:
--- a/src/python/grpcio/grpc/framework/alpha/_reexport.py
+++ b/src/python/grpcio/grpc/framework/alpha/_reexport.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -27,6 +27,8 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+import six
+
 from grpc.framework.common import cardinality
 from grpc.framework.face import exceptions as face_exceptions
 from grpc.framework.face import interfaces as face_interfaces
@ -181,7 +183,7 @@ def common_cardinality(early_adopter_cardinality):

 def common_cardinalities(early_adopter_cardinalities):
  common_cardinalities = {}
-  for name, early_adopter_cardinality in early_adopter_cardinalities.iteritems():
+  for name, early_adopter_cardinality in six.iteritems(early_adopter_cardinalities):
    common_cardinalities[name] = _EARLY_ADOPTER_CARDINALITY_TO_COMMON_CARDINALITY[
        early_adopter_cardinality]
  return common_cardinalities
--- a/src/python/grpcio/grpc/framework/crust/implementations.py
+++ b/src/python/grpcio/grpc/framework/crust/implementations.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -29,6 +29,8 @@

 """Entry points into the Crust layer of RPC Framework."""

+import six
+
 from grpc.framework.common import cardinality
 from grpc.framework.common import style
 from grpc.framework.crust import _calls
@ -271,7 +273,7 @@ class _DynamicStub(face.DynamicStub):

 def _adapt_method_implementations(method_implementations, pool):
  adapted_implementations = {}
-  for name, method_implementation in method_implementations.iteritems():
+  for name, method_implementation in six.iteritems(method_implementations):
    if method_implementation.style is style.Service.INLINE:
      if method_implementation.cardinality is cardinality.Cardinality.UNARY_UNARY:
        adapted_implementations[name] = _service.adapt_inline_unary_unary(
--- a/src/python/grpcio/grpc/framework/face/implementations.py
+++ b/src/python/grpcio/grpc/framework/face/implementations.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -29,6 +29,8 @@

 """Entry points into the Face layer of RPC Framework."""

+import six
+
 from grpc.framework.common import cardinality
 from grpc.framework.common import style
 from grpc.framework.base import exceptions as _base_exceptions
@ -228,7 +230,7 @@ class _DynamicStub(interfaces.DynamicStub):

 def _adapt_method_implementations(method_implementations, pool):
  adapted_implementations = {}
-  for name, method_implementation in method_implementations.iteritems():
+  for name, method_implementation in six.iteritems(method_implementations):
    if method_implementation.style is style.Service.INLINE:
      if method_implementation.cardinality is cardinality.Cardinality.UNARY_UNARY:
        adapted_implementations[name] = _service.adapt_inline_value_in_value_out(
--- a/src/python/grpcio/tests/unit/_core_over_links_base_interface_test.py
+++ b/src/python/grpcio/tests/unit/_core_over_links_base_interface_test.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -35,6 +35,8 @@ import random
 import time
 import unittest

+import six
+
 from grpc._adapter import _intermediary_low
 from grpc._links import invocation
 from grpc._links import service
@ -68,7 +70,7 @@ def _serialization_behaviors_from_serializations(serializations):
  request_deserializers = {}
  response_serializers = {}
  response_deserializers = {}
-  for (group, method), serialization in serializations.iteritems():
+  for (group, method), serialization in six.iteritems(serializations):
    request_serializers[group, method] = serialization.serialize_request
    request_deserializers[group, method] = serialization.deserialize_request
    response_serializers[group, method] = serialization.serialize_response
--- a/src/python/grpcio/tests/unit/_crust_over_core_over_links_face_interface_test.py
+++ b/src/python/grpcio/tests/unit/_crust_over_core_over_links_face_interface_test.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -32,6 +32,8 @@
 import collections
 import unittest

+import six
+
 from grpc._adapter import _intermediary_low
 from grpc._links import invocation
 from grpc._links import service
@ -59,7 +61,7 @@ def _serialization_behaviors_from_test_methods(test_methods):
  request_deserializers = {}
  response_serializers = {}
  response_deserializers = {}
-  for (group, method), test_method in test_methods.iteritems():
+  for (group, method), test_method in six.iteritems(test_methods):
    request_serializers[group, method] = test_method.serialize_request
    request_deserializers[group, method] = test_method.deserialize_request
    response_serializers[group, method] = test_method.serialize_response
@ -108,7 +110,7 @@ class _Implementation(test_interfaces.Implementation):
    # _digest.TestServiceDigest.
    cardinalities = {
        method: method_object.cardinality()
-        for (group, method), method_object in methods.iteritems()}
+        for (group, method), method_object in six.iteritems(methods)}
    dynamic_stub = crust_implementations.dynamic_stub(
        invocation_end_link, group, cardinalities, pool)

--- a/src/python/grpcio/tests/unit/beta/_face_interface_test.py
+++ b/src/python/grpcio/tests/unit/beta/_face_interface_test.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -32,6 +32,8 @@
 import collections
 import unittest

+import six
+
 from grpc.beta import implementations
 from grpc.beta import interfaces
 from tests.unit import resources
@ -57,7 +59,7 @@ def _serialization_behaviors_from_test_methods(test_methods):
  request_deserializers = {}
  response_serializers = {}
  response_deserializers = {}
-  for (group, method), test_method in test_methods.iteritems():
+  for (group, method), test_method in six.iteritems(test_methods):
    request_serializers[group, method] = test_method.serialize_request
    request_deserializers[group, method] = test_method.deserialize_request
    response_serializers[group, method] = test_method.serialize_response
@ -79,7 +81,7 @@ class _Implementation(test_interfaces.Implementation):
    # _digest.TestServiceDigest.
    cardinalities = {
        method: method_object.cardinality()
-        for (group, method), method_object in methods.iteritems()}
+        for (group, method), method_object in six.iteritems(methods)}

    server_options = implementations.server_options(
        request_deserializers=serialization_behaviors.request_deserializers,
--- a/src/python/grpcio/tests/unit/framework/_crust_over_core_face_interface_test.py
+++ b/src/python/grpcio/tests/unit/framework/_crust_over_core_face_interface_test.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -32,6 +32,8 @@
 import collections
 import unittest

+import six
+
 from grpc.framework.core import implementations as core_implementations
 from grpc.framework.crust import implementations as crust_implementations
 from grpc.framework.foundation import logging_pool
@ -66,7 +68,7 @@ class _Implementation(test_interfaces.Implementation):
    # _digest.TestServiceDigest.
    cardinalities = {
        method: method_object.cardinality()
-        for (group, method), method_object in methods.iteritems()}
+        for (group, method), method_object in six.iteritems(methods)}
    dynamic_stub = crust_implementations.dynamic_stub(
        invocation_end_link, group, cardinalities, pool)

--- a/src/python/grpcio/tests/unit/framework/face/testing/blocking_invocation_inline_service_test_case.py
+++ b/src/python/grpcio/tests/unit/framework/face/testing/blocking_invocation_inline_service_test_case.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -33,6 +33,8 @@
 import abc
 import unittest  # pylint: disable=unused-import

+import six
+
 from grpc.framework.face import exceptions
 from tests.unit.framework.common import test_constants
 from tests.unit.framework.face.testing import control
@ -72,7 +74,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testSuccessfulUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -83,7 +85,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testSuccessfulUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -95,7 +97,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testSuccessfulStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -106,7 +108,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testSuccessfulStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -118,7 +120,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testSequentialInvocations(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -135,7 +137,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testExpiredUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -146,7 +148,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testExpiredUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -158,7 +160,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testExpiredStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -169,7 +171,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testExpiredStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -181,7 +183,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testFailedUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -191,7 +193,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testFailedUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -202,7 +204,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testFailedStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -212,7 +214,7 @@ class BlockingInvocationInlineServiceTestCase(

  def testFailedStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

--- a/src/python/grpcio/tests/unit/framework/face/testing/digest.py
+++ b/src/python/grpcio/tests/unit/framework/face/testing/digest.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -32,6 +32,8 @@
 import collections
 import threading

+import six
+
 # testing_control, interfaces, and testing_service are referenced from
 # specification in this module.
 from grpc.framework.common import cardinality
@ -368,7 +370,7 @@ def _assemble(
  events = {}
  adaptations = {}
  messages = {}
-  for name, scenario in scenarios.iteritems():
+  for name, scenario in six.iteritems(scenarios):
    if name in names:
      raise ValueError('Repeated name "%s"!' % name)

--- a/src/python/grpcio/tests/unit/framework/face/testing/event_invocation_synchronous_event_service_test_case.py
+++ b/src/python/grpcio/tests/unit/framework/face/testing/event_invocation_synchronous_event_service_test_case.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -32,6 +32,8 @@
 import abc
 import unittest

+import six
+
 from grpc.framework.face import interfaces
 from tests.unit.framework.common import test_constants
 from tests.unit.framework.face.testing import callback as testing_callback
@ -72,7 +74,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testSuccessfulUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -87,7 +89,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testSuccessfulUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -102,7 +104,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testSuccessfulStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = testing_callback.Callback()
@ -120,7 +122,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testSuccessfulStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = testing_callback.Callback()
@ -138,7 +140,7 @@ class EventInvocationSynchronousEventServiceTestCase(
  def testSequentialInvocations(self):
    # pylint: disable=cell-var-from-loop
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -163,7 +165,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testExpiredUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -178,7 +180,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testExpiredUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -193,7 +195,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testExpiredStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for unused_test_messages in test_messages_sequence:
        callback = testing_callback.Callback()

@ -206,7 +208,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testExpiredStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = testing_callback.Callback()
@ -221,7 +223,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testFailedUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -237,7 +239,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testFailedUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -253,7 +255,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testFailedStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = testing_callback.Callback()
@ -272,7 +274,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testFailedStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = testing_callback.Callback()
@ -289,7 +291,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testParallelInvocations(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        first_callback = testing_callback.Callback()
@ -316,7 +318,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testCancelledUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -332,7 +334,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testCancelledUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = testing_callback.Callback()
@ -347,7 +349,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testCancelledStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = testing_callback.Callback()
@ -364,7 +366,7 @@ class EventInvocationSynchronousEventServiceTestCase(

  def testCancelledStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for unused_test_messages in test_messages_sequence:
        callback = testing_callback.Callback()

--- a/src/python/grpcio/tests/unit/framework/face/testing/future_invocation_asynchronous_event_service_test_case.py
+++ b/src/python/grpcio/tests/unit/framework/face/testing/future_invocation_asynchronous_event_service_test_case.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -34,6 +34,8 @@ import contextlib
 import threading
 import unittest

+import six
+
 from grpc.framework.face import exceptions
 from grpc.framework.foundation import future
 from grpc.framework.foundation import logging_pool
@ -105,7 +107,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testSuccessfulUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -117,7 +119,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testSuccessfulUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -129,7 +131,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testSuccessfulStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        request_iterator = _PauseableIterator(iter(requests))
@ -145,7 +147,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testSuccessfulStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        request_iterator = _PauseableIterator(iter(requests))
@ -161,7 +163,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testSequentialInvocations(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -180,7 +182,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testExpiredUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -195,7 +197,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testExpiredUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -207,7 +209,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testExpiredStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -222,7 +224,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testExpiredStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -234,7 +236,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testFailedUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -253,7 +255,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testFailedUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -268,7 +270,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testFailedStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -287,7 +289,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testFailedStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -302,7 +304,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testParallelInvocations(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -324,7 +326,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testCancelledUnaryRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -338,7 +340,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testCancelledUnaryRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -352,7 +354,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testCancelledStreamRequestUnaryResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -366,7 +368,7 @@ class FutureInvocationAsynchronousEventServiceTestCase(

  def testCancelledStreamRequestStreamResponse(self):
    for name, test_messages_sequence in (
-        self.digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self.digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

--- a/src/python/grpcio/tests/unit/framework/interfaces/face/_blocking_invocation_inline_service.py
+++ b/src/python/grpcio/tests/unit/framework/interfaces/face/_blocking_invocation_inline_service.py
@ -34,6 +34,8 @@ import itertools
 import unittest
 from concurrent import futures

+import six
+
 # test_interfaces is referenced from specification in this module.
 from grpc.framework.foundation import logging_pool
 from grpc.framework.interfaces.face import face
@ -81,7 +83,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -92,7 +94,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -104,7 +106,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -115,7 +117,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -127,7 +129,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSequentialInvocations(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -145,7 +147,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
  def testParallelInvocations(self):
    pool = logging_pool.pool(test_constants.PARALLELISM)
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = []
        response_futures = []
@ -167,7 +169,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
  def testWaitingForSomeButNotAllParallelInvocations(self):
    pool = logging_pool.pool(test_constants.PARALLELISM)
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = []
        response_futures_to_indices = {}
@ -205,7 +207,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -216,7 +218,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -228,7 +230,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -239,7 +241,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -251,7 +253,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -261,7 +263,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -272,7 +274,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -282,7 +284,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

--- a/src/python/grpcio/tests/unit/framework/interfaces/face/_digest.py
+++ b/src/python/grpcio/tests/unit/framework/interfaces/face/_digest.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -32,6 +32,8 @@
 import collections
 import threading

+import six
+
 # test_control, _service, and test_interfaces are referenced from specification
 # in this module.
 from grpc.framework.common import cardinality
@ -363,7 +365,7 @@ def _assemble(
  events = {}
  adaptations = {}
  messages = {}
-  for identifier, scenario in scenarios.iteritems():
+  for identifier, scenario in six.iteritems(scenarios):
    if identifier in identifiers:
      raise ValueError('Repeated identifier "(%s, %s)"!' % identifier)

--- a/src/python/grpcio/tests/unit/framework/interfaces/face/_future_invocation_asynchronous_event_service.py
+++ b/src/python/grpcio/tests/unit/framework/interfaces/face/_future_invocation_asynchronous_event_service.py
@ -36,6 +36,8 @@ import threading
 import unittest
 from concurrent import futures

+import six
+
 # test_interfaces is referenced from specification in this module.
 from grpc.framework.foundation import logging_pool
 from grpc.framework.interfaces.face import face
@ -141,7 +143,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = _Callback()
@ -156,7 +158,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -168,7 +170,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        request_iterator = _PauseableIterator(iter(requests))
@ -188,7 +190,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSuccessfulStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        request_iterator = _PauseableIterator(iter(requests))
@ -204,7 +206,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testSequentialInvocations(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -223,7 +225,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testParallelInvocations(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        first_request = test_messages.request()
        second_request = test_messages.request()
@ -239,7 +241,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
        test_messages.verify(second_request, second_response, self)

    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = []
        response_futures = []
@ -259,7 +261,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
  def testWaitingForSomeButNotAllParallelInvocations(self):
    pool = logging_pool.pool(test_constants.PARALLELISM)
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = []
        response_futures_to_indices = {}
@ -281,7 +283,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testCancelledUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = _Callback()
@ -298,7 +300,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testCancelledUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -312,7 +314,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testCancelledStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = _Callback()
@ -329,7 +331,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testCancelledStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -343,7 +345,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = _Callback()
@ -360,7 +362,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -372,7 +374,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = _Callback()
@ -389,7 +391,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testExpiredStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

@ -401,7 +403,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedUnaryRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()
        callback = _Callback()
@ -423,7 +425,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedUnaryRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.unary_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        request = test_messages.request()

@ -438,7 +440,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedStreamRequestUnaryResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_unary_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()
        callback = _Callback()
@ -460,7 +462,7 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):

  def testFailedStreamRequestStreamResponse(self):
    for (group, method), test_messages_sequence in (
-        self._digest.stream_stream_messages_sequences.iteritems()):
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
      for test_messages in test_messages_sequence:
        requests = test_messages.requests()

--- a/src/python/grpcio/tests/unit/test_common.py
+++ b/src/python/grpcio/tests/unit/test_common.py
@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@ -31,6 +31,8 @@

 import collections

+import six
+
 INVOCATION_INITIAL_METADATA = ((b'0', b'abc'), (b'1', b'def'), (b'2', b'ghi'),)
 SERVICE_INITIAL_METADATA = ((b'3', b'jkl'), (b'4', b'mno'), (b'5', b'pqr'),)
 SERVICE_TERMINAL_METADATA = ((b'6', b'stu'), (b'7', b'vwx'), (b'8', b'yza'),)
@ -65,7 +67,7 @@ def metadata_transmitted(original_metadata, transmitted_metadata):
    key, value = tuple(key_value_pair)
    transmitted[key].append(value)

-  for key, values in original.iteritems():
+  for key, values in six.iteritems(original):
    transmitted_values = transmitted[key]
    transmitted_iterator = iter(transmitted_values)
    try: