code: def clear(self, split):
          
          for candidate_class in self.candidate_classes:
              logger.info(
                  f"Clearing table {candidate_class.__tablename__} (split {split})"
              )
              self.session.query(Candidate).filter(
                  Candidate.type == candidate_class.__tablename__
              ).filter(Candidate.split == split).delete(synchronize_session="fetch")
docs: Delete Candidates of each class initialized with the
          CandidateExtractor from given split the database.
  
          :param split: Which split to clear.
          :type split: int