4Where after the date of the commencement of this Act a person is alleged—
(a)to have committed an offence continuing over a period beginning before that date and ending thereon or thereafter ; or
(b)to have committed an offence between two dates falling within such a period,
and the offence would be an offence against this Act if this Act had been in force at all material times, he may be proceeded against as if this Act had so been in force.