class_docstr: Implementation of lock with the file system as the backend for synchronization.
  This version patches for the `FileLock._expiry_time` crash(https://github.com/py-sherlock/sherlock/issues/71)
  
  `sherlock.FileLock` might not work as expected for Python threads.
  It uses re-entrant OS locks, meaning that multiple Python threads could acquire the lock at the same time.
  For different processes/OS threads, the file lock will work as expected.
  We need to patch the lock to handle Python threads too.
code: def _locked(self):
      if self._lock_py_thread.locked():
          return True
  
      if not self._lock_file_enabled:
          return False
  
      if not self._data_file.exists():
          # File doesn't exist so can't be locked.
          return False
  
      with self._lock_file:
          data = None
          for _retry in range(10):
              try:
                  data = json.loads(self._data_file.read_text())
                  break
              except BaseException:
                  time.sleep(0.1)
  
      if data is None:
          return False
  
      if self._has_expired(data, self._now()):
          # File exists but has expired.
          return False
  
      # Lease exists and has not expired.
      return True
  
imports: from collections import defaultdict
  import datetime
  import json
  from pathlib import Path
  import threading
  import time
  from typing import Callable
  from typing import Dict
  from typing import Optional
  import uuid
  from pydantic import BaseModel
  import redis
  from sherlock.lock import BaseLock
  from sherlock.lock import FileLock
  from sherlock.lock import RedisLock
  from ..serde.serializable import serializable
label_desc: Use image node_id 7 for calling the PatchedFileLock obj's underlying member method code with example usage: obj._locked() and returns: True, True, False, False, False, False