(b)retain in his custody any such books or documents for a period exceeding fifteen days (exclusive of holidays) without obtaining the approval of ] [ Substituted by Act 46 of 1964, Section 35, for section 37 (w.e.f. 1.4.1965).][the Chief Commissioner or Director-General or Commissioner or Director therefor, as the case may be] [ Substituted by Act 26 of 1988, Section 64, for " the Chief Commissioner or Commissioner therefor" (w.e.f. 1.6.1988).].