def __call__(self):
        """
        Try to list table names just to reach the db.
        """
        if self.must_fail:
            return False

        for conn in connections.all():
            try:
                if self.working_status not in conn.connection.status:
                    return False
            except AttributeError as e:
                return None
        else:
            return True
dataset/ETHPy150Open scieloorg/scielo-manager/scielomanager/health/checks.py/PGConnection.__call__/swapped operands of `not in`