code: def test_assert_valid_hook_call(self, mock_hook):
      task = CloudMemorystoreListInstancesOperator(
          task_id=TEST_TASK_ID,
          location=TEST_LOCATION,
          page_size=TEST_PAGE_SIZE,
          project_id=TEST_PROJECT_ID,
          retry=TEST_RETRY,
          timeout=TEST_TIMEOUT,
          metadata=TEST_METADATA,
          gcp_conn_id=TEST_GCP_CONN_ID,
          impersonation_chain=TEST_IMPERSONATION_CHAIN,
      )
      task.execute(mock.MagicMock())
      mock_hook.assert_called_once_with(
          gcp_conn_id=TEST_GCP_CONN_ID,
          impersonation_chain=TEST_IMPERSONATION_CHAIN,
      )
      mock_hook.return_value.list_instances.assert_called_once_with(
          location=TEST_LOCATION,
          page_size=TEST_PAGE_SIZE,
          project_id=TEST_PROJECT_ID,
          retry=TEST_RETRY,
          timeout=TEST_TIMEOUT,
          metadata=TEST_METADATA,
      )
  
imports: from __future__ import annotations
  from unittest import mock
  from google.api_core.gapic_v1.method import DEFAULT
  from google.cloud.memcache_v1beta2.types import cloud_memcache
  from google.cloud.redis_v1 import FailoverInstanceRequest
  from google.cloud.redis_v1.types import Instance
  from airflow.providers.google.cloud.operators.cloud_memorystore import CloudMemorystoreCreateInstanceAndImportOperator, CloudMemorystoreCreateInstanceOperator, CloudMemorystoreDeleteInstanceOperator, CloudMemorystoreExportInstanceOperator, CloudMemorystoreFailoverInstanceOperator, CloudMemorystoreGetInstanceOperator, CloudMemorystoreImportOperator, CloudMemorystoreListInstancesOperator, CloudMemorystoreMemcachedCreateInstanceOperator, CloudMemorystoreMemcachedDeleteInstanceOperator, CloudMemorystoreMemcachedGetInstanceOperator, CloudMemorystoreMemcachedListInstancesOperator, CloudMemorystoreMemcachedUpdateInstanceOperator, CloudMemorystoreScaleInstanceOperator, CloudMemorystoreUpdateInstanceOperator
label_desc: Use image node_id 1 for calling the TestCloudMemorystoreListInstancesOperator obj's underlying member method code with example usage: obj.test_assert_valid_hook_call(mock_hook) without return types