code: def sync(self):
          
          if self._sync:
              return  # opened in sync mode, so skip the manual sync
          self._sync = True
          for ekey in self._buffer:
              filename = self._key_to_filename(ekey)
              self._write_to_file(filename, self._buffer[ekey])
          self._buffer.clear()
          self._sync = False
docs: Sync the write buffer with the cache files and clear the buffer.
  
          If the :class:`FileCache` object was opened with the optional ``'s'``
          *flag* argument, then calling :meth:`sync` will do nothing.