code: def close(self, needs_lock=True):
          
          # TODO: remove needs_lock if/when we have a reentrant lock in
          # dask.distributed: https://github.com/dask/dask/issues/3832
          with self._optional_lock(needs_lock):
              default = None
              file = self._cache.pop(self._key, default)
              if file is not None:
                  file.close()
docs: Explicitly close any associated file object (if necessary).