code: def testFixed64(self):
      value = self.GetUnknownField("optional_fixed64")
      self.assertEqual(self.all_fields.optional_fixed64, value)
  
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 7 for calling the UnknownFieldsAccessorsTest obj's underlying member method code with example usage: obj.testFixed64() without return types