def METHOD_NAME(self, file_ref):
    self._logger.info("unload %s" % file_ref)
    for group in self._file_to_groups[file_ref]:
        self._group_dict[group].remove(file_ref)
    station = self.get_MT_obj(file_ref).station
    del self._station_dict[station]
    del self._file_to_groups[file_ref]
    del self._file_dict[file_ref]