code: def test_create_subscription_nofailifexists(self, mock_service):
      mock_service.create_subscription.side_effect = AlreadyExists(
          f"Subscription already exists: {EXPANDED_SUBSCRIPTION}"
      )
      response = self.pubsub_hook.create_subscription(
          project_id=TEST_PROJECT,
          topic=TEST_TOPIC,
          subscription=TEST_SUBSCRIPTION,
      )
      assert TEST_SUBSCRIPTION == response
  
imports: from __future__ import annotations
  from unittest import mock
  from uuid import UUID
  import httplib2
  import pytest
  from google.api_core.exceptions import AlreadyExists, GoogleAPICallError
  from google.api_core.gapic_v1.method import DEFAULT
  from google.cloud.exceptions import NotFound
  from google.cloud.pubsub_v1.types import ReceivedMessage
  from googleapiclient.errors import HttpError
  from airflow.providers.google.cloud.hooks.pubsub import PubSubAsyncHook, PubSubException, PubSubHook
  from airflow.providers.google.common.consts import CLIENT_INFO
  from airflow.version import version
label_desc: Use image node_id 22 for calling the TestPubSubHook obj's underlying member method code with example usage: obj.test_create_subscription_nofailifexists(mock_service) without return types