def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def _check_sigint_gate_is_correct(self):
        assert (
            self._threads_ignoring_sigint >= 0
        ), "This should never happen, someone must have modified the counter outside of SignalHandler."