code: def _save_file_and_pos(self):
          
          if not self._pos_changed:
              return
          with open(self.pos_storage_filename, 'w+') as f:
              _pos = '%s:%s' % (self._log_file, self._log_pos)
              _logger.debug('Saving position %s to file %s'
                            % (_pos, self.pos_storage_filename))
              f.write(_pos)
              self._pos_changed = False
docs: Save current position into file