<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def clear_all(self, split):
 """Delete ALL Candidates from given split the database. :param split: Which split to clear. :type split: int """

        logger.info("Clearing ALL Candidates.")
        self.session.query(Candidate).filter(Candidate.split == split).delete(
            synchronize_session="fetch"
        )