diff --git a/src/python/grpcio/commands.py b/src/python/grpcio/commands.py
index d189c2869d0..a31c9730661 100644
--- a/src/python/grpcio/commands.py
+++ b/src/python/grpcio/commands.py
@@ -217,6 +217,7 @@ class BuildExt(build_ext.build_ext):
             """Test if default compiler is okay with specifying c++ version
             when invoked in C mode. GCC is okay with this, while clang is not.
             """
+            # TODO(lidiz) Remove the generated a.out for success tests.
             cc_test = subprocess.Popen(
                 ['cc', '-x', 'c', '-std=c++11', '-'],
                 stdin=subprocess.PIPE,