code: def testUnknownExtensions(self):
      message = unittest_pb2.TestEmptyMessageWithExtensions()
      message.ParseFromString(self.all_fields_data)
      self.assertEqual(
          message.SerializeToString(), self.all_fields_data
      )
  
imports: from google.protobuf import unittest_mset_pb2
  from google.protobuf import unittest_pb2
  from google.protobuf import unittest_proto3_arena_pb2
  from google.protobuf.internal import api_implementation
  from google.protobuf.internal import encoder
  from google.protobuf.internal import message_set_extensions_pb2
  from google.protobuf.internal import missing_enum_values_pb2
  from google.protobuf.internal import test_util
  from google.protobuf.internal import testing_refleaks
  from google.protobuf.internal import type_checkers
label_desc: Use image node_id 13 for calling the UnknownFieldsAccessorsTest obj's underlying member method code with example usage: obj.testUnknownExtensions() without return types