In the presentcase, as observed earlier, the assessee not only responded to the notice under Section 148 of the Act within one month, but on the basis of the return filed earlier, participated in the proceedings till the matter reached the FAA and was disposed of. A glance at Section 292B of the Act, shows that under this provision, certain Acts are not to be treated as invalid, may be by reason of any mistake, defect or omissions, either in return of income, assessment, notice, summons or other proceedings. In other words, a notice cannot be invalidated by reason of any mistake, such as the one occurred in the presentcase, namely, the period of filing return of income was not specified as contemplated by Section 148 of the Act. If such a defect is not allowed to be cured, or treated as invalid so as to declare the notice invalid, despite the fact that assessee had taken that notice as valid and responded to it in letter and spirit and participated in the proceedings, the very purpose/objective of the provisions contained in Section 292B of the Act would stand frustrated/defeated.