code: def CheckDurationConversion(self, message, text):
      self.assertEqual(text, message.ToJsonString())
      parsed_message = duration_pb2.Duration()
      parsed_message.FromJsonString(text)
      self.assertEqual(message, parsed_message)
  
imports: from datetime import datetime
  from google.protobuf import any_pb2
  from google.protobuf import duration_pb2
  from google.protobuf import field_mask_pb2
  from google.protobuf import struct_pb2
  from google.protobuf import timestamp_pb2
  from google.protobuf import unittest_pb2
  from google.protobuf.internal import any_test_pb2
  from google.protobuf.internal import test_util
  from google.protobuf.internal import well_known_types
  from google.protobuf import descriptor
  from google.protobuf import text_format
label_desc: Use image node_id 2 for calling the TimeUtilTestBase obj's underlying member method code with example usage: obj.CheckDurationConversion(message, text) without return types