def is_user_valid(self, cred_id):
        """
        Check if this User ID is valid.
        """
        q = select(self.CredentialsTable).filter(self.CredentialsTable.c.id == cred_id)
        results = self.sess.execute(q).all()
        return len(results) > 0

        Check if this User ID is valid.
        
cme/protocols/ssh/database.py