21. (1) No person shall enter into any contract or agreement which would directly or indirectly evade or avoid in any way the operation of any provision of this Act or of any rule, direction or order made thereunder. (2) Any provisions of, or having effect under, this Act that a thing shall not be done without the permission of the Government or the Bangladesh Bank, shall not render invalid any agreement by any person to do that thing, if it is a term of the agreement that that thing shall not be done unless permission is granted by the Government or the Bangladesh Bank, as the case may be; and it shall be an implied term of every contract governed by the law of any part of Bangladesh that anything agreed to be done by any term of that contract which is prohibited to be done by or under any of the provisions of this Act except with the permission of the Government or the Bangladesh Bank, shall not be done unless such permission is granted. (3) Neither the provisions of this Act nor any term (whether expressed or implied) contained in any contract that anything for which the permission of the Government or the Bangladesh Bank is required by the said provisions shall not be done without that permission, shall prevent legal proceedings being brought in Bangladesh to recover any sum which, apart from the said provisions and any such term, would be due, whether as a debt, damages or otherwise, but -(a) the said provisions shall apply to sums required to be paid by any judgment or order of any Court as they apply in relation to other sums; and (b) no steps shall be taken for the purpose of enforcing any judgment or order for the payment of any sum to which the said provisions apply except as respects so much thereof as the Government or the Bangladesh Bank, as the case may be, may permit to be paid; and(c) for the purpose of considering whether or not to grant such permission, the Government or the Bangladesh Bank, as the case may be, may require the person entitled to the benefit of the judgment or order and the debtor under the judgment or order, to produce such documents and to give such information as may be specified in the requirement. (4) Notwithstanding anything in the Negotiable Instruments Act, 1881, neither the provisions of this Act or of any rule, direction or order made thereunder, nor any condition, whether express or to be implied having regard to those provisions, that any payment shall not be made without permission under this Act, shall be deemed to prevent any instrument being a bill of exchange or promissory note.