diff --git a/python/google/protobuf/internal/generator_test.py b/python/google/protobuf/internal/generator_test.py
index 0f4ad64620de..d11cb8d03335 100644
--- a/python/google/protobuf/internal/generator_test.py
+++ b/python/google/protobuf/internal/generator_test.py
@@ -19,6 +19,7 @@
 import unittest
 
 from google.protobuf.internal import test_bad_identifiers_pb2
+from google.protobuf import service
 from google.protobuf import symbol_database
 from google.protobuf import unittest_import_pb2
 from google.protobuf import unittest_import_public_pb2
@@ -282,6 +283,12 @@ def testNoGenericServices(self):
     self.assertTrue(hasattr(unittest_no_generic_services_pb2, "FOO"))
     self.assertTrue(hasattr(unittest_no_generic_services_pb2, "test_extension"))
 
+    # Make sure unittest_no_generic_services_pb2 has no services subclassing
+    # Proto2 Service class.
+    if hasattr(unittest_no_generic_services_pb2, "TestService"):
+      self.assertFalse(issubclass(unittest_no_generic_services_pb2.TestService,
+                                  service.Service))
+
   def testMessageTypesByName(self):
     file_type = unittest_pb2.DESCRIPTOR
     self.assertEqual(
diff --git a/python/google/protobuf/internal/service_reflection_test.py b/python/google/protobuf/internal/service_reflection_test.py
index ca9e70a3807a..1a809d5e3968 100644
--- a/python/google/protobuf/internal/service_reflection_test.py
+++ b/python/google/protobuf/internal/service_reflection_test.py
@@ -13,21 +13,21 @@
 import unittest
 
 from google.protobuf import service_reflection
+from google.protobuf import service
 from google.protobuf import unittest_pb2
 
 
 class FooUnitTest(unittest.TestCase):
 
   def testService(self):
-
-    class MockRpcChannel:
+    class MockRpcChannel(service.RpcChannel):
       def CallMethod(self, method, controller, request, response, callback):
         self.method = method
         self.controller = controller
         self.request = request
         callback(response)
 
-    class MockRpcController:
+    class MockRpcController(service.RpcController):
       def SetFailed(self, msg):
         self.failure_message = msg
 
@@ -81,8 +81,7 @@ def Bar(self, rpc_controller, request, done):
     self.assertEqual(True, srvc.bar_called)
 
   def testServiceStub(self):
-
-    class MockRpcChannel:
+    class MockRpcChannel(service.RpcChannel):
       def CallMethod(self, method, controller, request,
                      response_class, callback):
         self.method = method
diff --git a/python/google/protobuf/service.py b/python/google/protobuf/service.py
index 8002c040ffd9..38b8217919cb 100644
--- a/python/google/protobuf/service.py
+++ b/python/google/protobuf/service.py
@@ -70,12 +70,12 @@ def CallMethod(self, method_descriptor, rpc_controller,
     Postconditions:
 
     * "done" will be called when the method is complete.  This may be
-     before CallMethod() returns or it may be at some point in the future.
+      before CallMethod() returns or it may be at some point in the future.
     * If the RPC failed, the response value passed to "done" will be None.
-     Further details about the failure can be found by querying the
-     RpcController.
+      Further details about the failure can be found by querying the
+      RpcController.
     """
-   raise NotImplementedError
+    raise NotImplementedError
 
   def GetRequestClass(self, method_descriptor):
     """Returns the class of the request message for the specified method.