code: def GetFileObjectReferenceCount(self, path_spec):
      
      cache_value = self._file_object_cache.GetCacheValue(path_spec.comparable)
      if not cache_value:
        return None
  
      return cache_value.reference_count
docs: Retrieves the reference count of a cached file-like object.
  
      Args:
        path_spec (PathSpec): path specification.
  
      Returns:
        int: reference count or None if there is no file-like object for
            the corresponding path specification cached.