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 test_validate_change_skill_difficulty_none(self):
        expected_suggestion_dict = self.suggestion_dict
        suggestion = suggestion_registry.SuggestionAddQuestion(
            expected_suggestion_dict['suggestion_id'],
            expected_suggestion_dict['target_id'],
            expected_suggestion_dict['target_version_at_submission'],
            expected_suggestion_dict['status'], self.author_id,
            self.reviewer_id, expected_suggestion_dict['change'],
            expected_suggestion_dict['score_category'],
            expected_suggestion_dict['language_code'], False, self.fake_date)
        suggestion.validate()

        suggestion.change.skill_difficulty = None

        with self.assertRaisesRegex(
            utils.ValidationError, 'Expected change to contain skill_difficulty'
        ):
            suggestion.validate()