Rule 4520. Certificate or affidavit of public officer. Where a public
officer is required or authorized, by special provision of law, to make
a certificate or an affidavit to a fact ascertained, or an act
performed, by him in the course of his official duty, and to file or
deposit it in a public office of the state, the certificate or affidavit
so filed or deposited is prima facie evidence of the facts stated.