Return of tax base, etc., not to be invalid on certain grounds
276. A return of tax bases, assessment, notice, summon or any other proceeding, under this Code shall be deemed to be valid, regardless of the fact that there is a mistake, defect or omission in the return of tax bases, assessment, notice, summon or other proceeding, if the return of income, assessment, notice, summon or any other proceeding is in substance and effect in conformity with, or according to the intent and purpose of, this Code.
