Every licence, written permission, notice, bill, summons or other document which is required by this Act or any rule or bye-law made thereunder to bear the signature of the Municipal Commissioner or the Chief Officer or of any municipal officer, shall be deemed to be properly signed if it bears a facsimile of the signature of such Commissioner or Chief Officer, as the case may be, stamped thereupon:

Provided that nothing in this section shall be deemed to apply to a cheque drawn upon the municipal fund or any contract executed on behalf of the municipal council.