Proof of consent etc., of municipal authorities or municipal officers.-

Whenever under this Act or any rule or byelaw made there under, the doing or the omitting to do anything or the validity of anything depends upon the approval, sanction, consent, concurrence, declaration, opinion or satisfaction of(a) the Corporation, or the Mayor-in Council or the Commissioner, or (b) of any municipal officer; a written document purporting to have been signed in case-(a) by the Commissioner, and in case(b) by the said municipal officer, purporting to convey or set forth such approval, sanction, consent, concurrence, declaration, opinion or satisfaction shall be prima facie evidence thereof.