Run yapf over Python code
diff --git a/src/python/grpcio_tests/commands.py b/src/python/grpcio_tests/commands.py
index 845b7f5..af0ffe3 100644
--- a/src/python/grpcio_tests/commands.py
+++ b/src/python/grpcio_tests/commands.py
@@ -121,8 +121,8 @@
                 '--grpc_python_out={}'.format(PROTO_STEM),
             ] + [path]
             if protoc.main(command) != 0:
-                sys.stderr.write('warning: Command:\n{}\nFailed'.format(
-                    command))
+                sys.stderr.write(
+                    'warning: Command:\n{}\nFailed'.format(command))
 
         # Generated proto directories dont include __init__.py, but
         # these are needed for python package resolution