Enable unused-argument lint

.pylintrc

@@ -25,7 +25,6 @@ notes=FIXME,XXX
 #TODO: Enable locally-disabled
 #TODO: Enable protected-access
 #TODO: Enable no-name-in-module
-#TODO: Enable unused-argument
 #TODO: Enable wrong-import-order
 # TODO(https://github.com/PyCQA/pylint/issues/59#issuecomment-283774279):
 # enable cyclic-import after a 1.7-or-later pylint release that recognizes our
@@ -38,4 +37,4 @@ notes=FIXME,XXX
 #TODO: Enable useless-else-on-loop
 #TODO: Enable too-many-nested-blocks
 
-disable=missing-docstring,too-few-public-methods,no-init,duplicate-code,invalid-name,locally-disabled,protected-access,no-name-in-module,unused-argument,wrong-import-order,cyclic-import,too-many-instance-attributes,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-nested-blocks
+disable=missing-docstring,too-few-public-methods,no-init,duplicate-code,invalid-name,locally-disabled,protected-access,no-name-in-module,wrong-import-order,cyclic-import,too-many-instance-attributes,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-nested-blocks

src/python/grpcio/grpc/_channel.py

@@ -237,7 +237,7 @@ def _consume_request_iterator(request_iterator, state, call,
                     cygrpc.Operations(operations), event_handler)
                 state.due.add(cygrpc.OperationType.send_close_from_client)
 
-    def stop_consumption_thread(timeout):
+    def stop_consumption_thread(timeout):  # pylint: disable=unused-argument
         with state.condition:
             if state.code is None:
                 call.cancel()
@@ -736,7 +736,7 @@ def _run_channel_spin_thread(state):
                         state.managed_calls = None
                         return
 
-    def stop_channel_spin(timeout):
+    def stop_channel_spin(timeout):  # pylint: disable=unused-argument
         with state.lock:
             if state.managed_calls is not None:
                 for call in state.managed_calls:
@@ -877,12 +877,8 @@ def _moot(state):
 def _subscribe(state, callback, try_to_connect):
     with state.lock:
         if not state.callbacks_and_connectivities and not state.polling:
-
-            def cancel_all_subscriptions(timeout):
-                _moot(state)
-
             polling_thread = _common.CleanupThread(
-                cancel_all_subscriptions,
+                lambda timeout: _moot(state),
                 target=_poll_connectivity,
                 args=(state, state.channel, bool(try_to_connect)))
             polling_thread.start()

src/python/grpcio/grpc/beta/_client_adaptations.py

@@ -35,7 +35,7 @@ from grpc.framework.common import cardinality
 from grpc.framework.foundation import future
 from grpc.framework.interfaces.face import face
 
-# pylint: disable=too-many-arguments,too-many-locals
+# pylint: disable=too-many-arguments,too-many-locals,unused-argument
 
 _STATUS_CODE_TO_ABORTION_KIND_AND_ABORTION_ERROR_CLASS = {
     grpc.StatusCode.CANCELLED: (face.Abortion.Kind.CANCELLED,

src/python/grpcio/grpc/beta/_server_adaptations.py

@@ -181,7 +181,7 @@ def _run_request_pipe_thread(request_iterator, request_consumer,
                 return
         request_consumer.terminate()
 
-    def stop_request_pipe(timeout):
+    def stop_request_pipe(timeout):  # pylint: disable=unused-argument
         thread_joined.set()
 
     request_pipe_thread = _common.CleanupThread(