code: def test_update_function_if_exists(self, mock_hook):
      mock_hook.return_value.get_function.return_value = True
      mock_hook.return_value.update_function.return_value = True
      op = CloudFunctionDeployFunctionOperator(
          project_id=GCP_PROJECT_ID,
          location=GCP_LOCATION,
          body=deepcopy(VALID_BODY),
          task_id="id",
      )
      op.execute(context=mock.MagicMock())
      mock_hook.assert_called_once_with(
          api_version="v1",
          gcp_conn_id="google_cloud_default",
          impersonation_chain=None,
      )
      mock_hook.return_value.get_function.assert_called_once_with(
          "projects/test_project_id/locations/test_region/functions/helloWorld"
      )
      expected_body = deepcopy(VALID_BODY)
      expected_body["labels"] = {
          "airflow-version": "v"
          + version.replace(".", "-").replace("+", "-")
      }
      mock_hook.return_value.update_function.assert_called_once_with(
          "projects/test_project_id/locations/test_region/functions/helloWorld",
          expected_body,
          expected_body.keys(),
      )
      mock_hook.return_value.create_new_function.assert_not_called()
  
imports: from __future__ import annotations
  from copy import deepcopy
  from unittest import mock
  import httplib2
  import pytest
  from googleapiclient.errors import HttpError
  from airflow.exceptions import AirflowException
  from airflow.providers.google.cloud.operators.functions import FUNCTION_NAME_PATTERN, CloudFunctionDeleteFunctionOperator, CloudFunctionDeployFunctionOperator, CloudFunctionInvokeFunctionOperator
  from airflow.version import version
label_desc: Use image node_id 3 for calling the TestGcfFunctionDeploy obj's underlying member method code with example usage: obj.test_update_function_if_exists(mock_hook) without return types