420. The certificate must set forth:(1) the name, residence, official capacity and signature of the person who has given it;
(2) a summary statement of the manner in which the notice was published or notified;
(3) the place, day and hour of publication or of notification.The truth of the facts set forth in such certificate must be attested under the oath of office of the person giving it, if such person has taken an oath of office, and, if not, by his special oath.
Such certificate is written either on the original notice or on a paper annexed thereto.