code: def close(self):
          
          self.sync()
          self.sync = self.create = self.delete = self._closed
          self._write_to_file = self._read_to_file = self._closed
          self._key_to_filename = self._filename_to_key = self._closed
          self.__getitem__ = self.__setitem__ = self.__delitem__ = self._closed
          self.__iter__ = self.__len__ = self.__contains__ = self._closed
docs: Sync the write buffer, then close the cache.
  
          If a closed :class:`FileCache` object's methods are called, a
          :exc:`ValueError` will be raised.