On the day fixed for opening the ballots pursuant to section 32-1113, the election commissioner or county clerk and the county canvassing board which officiated in making the official county canvass of the election returns shall proceed to open such ballots in the presence of the petitioner and the person whose election is contested or their attorneys. While the ballots are open and being examined, the election commissioner or county clerk shall exclude all other persons from the counting room. All persons witnessing the counting of ballots shall be placed under oath requiring them not to disclose any fact discovered from such ballots except as stated in the certificate of the election commissioner or county clerk.