When the secretary of the district has completed his examination of the petition, he shall attach to the same his certificate, properly dated, showing the result of such examination, and if from such examination he shall find that said petition is signed by the requisite number of voters or is not so signed, he shall certify that the same is sufficient or insufficient, as the case may be.
If, by the certificate of the secretary of the district, the petition is found to be insufficient, he shall also certify to the number of voters required to make such petition sufficient, and it may be amended by filing a supplemental petition or petitions within 10 days of the date of such certificate.