code: def testMergeSingleWord(self):
      message = unittest_pb2.TestAllTypes()
      text = "foo"
      self.assertRaisesWithMessage(
          text_format.ParseError,
          (
              '1:1 : Message type "protobuf_unittest.TestAllTypes" has no field named '
              '"foo".'
          ),
          text_format.Merge,
          text,
          message,
      )
  
imports: import difflib
  import re
  import unittest
  from google.protobuf import text_format
  from google.protobuf.internal import test_util
  from google.protobuf import unittest_pb2
  from google.protobuf import unittest_mset_pb2
label_desc: Use image node_id 26 for calling the TextFormatTest obj's underlying member method code with example usage: obj.testMergeSingleWord() without return types