Every contract, agreement, or arrangement made or entered into, orally or in writing, whether before or after the commencement of this Act, shall so far as it has or purports to have the purpose or effect of in any way, directly or indirectly:
(a) altering the incidence of any income tax;
(b) relieving any person from liability to pay any income tax or make any return;
(c) defeating, evading, or avoiding any duty or liability imposed on any person by this Act; or
(d) preventing the operation of this Act in any respect;
be absolutely void, as against the Commissioner, or in regard to any proceeding under this Act, but without prejudice to such validity as it may have in any other respect or for any other purpose.