Now, section 31 is in these terms : Section 31. "For the removal of doubts it is hereby declared that the provisions of 144 sub sections (1), (2) and (3) of section 34 of the principal Act shall apply and shall be deemed always to have applied to any assessment or re assessment for any year ending before the 1st day of April, 1948, in any case where proceedings in respect of such assessment or re assessment were commenced under the said sub sections after the 8th day of September, 1948, and any notice issued in accordance with sub section (1) or any assessment completed in pursuance of such notice within the time specified in sub section(3), whether before or after the commencement of the Indian Income tax (Amendment) Act, 1953, shall, notwithstanding any judgment or order of any Court, Appellate Tribunal or Incometax authority to the contrary, be deemed to have been validly issued or completed, as the case may be, and no such notice, assessment or re assessment shall be called in question on the ground merely that the provisions of section 34 did not apply or purport to apply in respect of an assessment or re assessment for any year prior to the 1st day of April 1948." No question as to sub section