code: def testExtensionsByName(self):
      file_type = unittest_pb2.DESCRIPTOR
      self.assertEqual(
          unittest_pb2.my_extension_string,
          file_type.extensions_by_name[
              unittest_pb2.my_extension_string.name
          ],
      )
  
imports: from google.protobuf.internal import test_bad_identifiers_pb2
  from google.protobuf import unittest_custom_options_pb2
  from google.protobuf import unittest_import_pb2
  from google.protobuf import unittest_import_public_pb2
  from google.protobuf import unittest_mset_pb2
  from google.protobuf import unittest_mset_wire_format_pb2
  from google.protobuf import unittest_no_generic_services_pb2
  from google.protobuf import unittest_pb2
  from google.protobuf import service
  from google.protobuf import symbol_database
label_desc: Use image node_id 19 for calling the GeneratorTest obj's underlying member method code with example usage: obj.testExtensionsByName() without return types