Negotiable Instruments Law
Section 5. Additional provisions not affecting negotiability.-An instrument which contains an order or promise to do any act in f addition to the payment of money is not negotiable. But the negotiable character of an instrument otherwise negotiable is not affected by a provision which-
(a) Authorizes the sale of collateral securities in case the instrument be not paid at maturity; or
(b) Authorizes a confession of judgment if the instrument be not paid at maturity; or
(c) Waives the benefit of any law intended for the advantage or protection of the obligor; or
(d) Gives the holder an election to require something to be done in lieu of payment of money.
But nothing in this section shall validate any provision or stipulation otherwise illegal.