code: def __init__(self, file_path: str):
      self._file_path = file_path
      self._modify_date = os.path.getmtime(file_path)
  
file_path: mars/mars/services/cluster/tests/backend.py
imports: import asyncio
  import logging
  import os
  from typing import Optional, List, AsyncGenerator
  from ...None import NodeRole
  from ...cluster.backends import AbstractClusterBackend, register_cluster_backend
label_desc: Use image node_id 1 to create a new TestClusterBackend object from inherited base classes: AbstractClusterBackend with example: obj = TestClusterBackend(file_path)