Notice of demand deemed from intimation under assessment and withholding provisions, including deductor liabilities, for tax assessments. Amendment substitutes the proviso to section 156 so that where any sum is determined to be payable by the assessee under the assessment intimation provision or by a deductor under the withholding intimation provision, the intimation under those provisions shall be deemed to be a notice of demand for the purposes of section 156, thereby treating intimations to deductors as enforceable notices of demand.