code: def _load_meta_cache(self):
          
          try:
              if self._should_invalidate_cache():
                  os.remove(self._cache_filename)
              else:
                  with open(self._cache_filename, 'rb') as f:
                      self._document_meta = compat.pickle.load(f)
          except (OSError, IOError, compat.pickle.PickleError,
                  ImportError, AttributeError):
              pass
docs: Try to load metadata from file.