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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def revoke_token(token_id, user):
 """ Revokes the given token. Raises a TokenNotFound error if the token does not exist in the database """

    try:
        token = TokenBlacklist.query.filter_by(id=token_id, user_identity=user).one()
        token.revoked = True
        db.session.commit()
    except NoResultFound:
        raise TokenNotFound("Could not find the token {}".format(token_id))