On or before the first of July the department shall deliver to the State Controller the record of assessments and charges, certified to by the director, which certificate shall be substantially as follows: “I, ____, Director of Conservation, do hereby certify that between the first of March and the first of July, 20__, I made diligent inquiry and examination to ascertain all property and persons, firms, corporations and associations subject to assessment as required by the provisions of this chapter, providing for the assessment and collection of charges; that I have faithfully complied with all the duties imposed upon me by law; that I have not imposed any unjust or double assessment through malice or ill will or otherwise; nor allowed any person, firm, corporation, or association, or property to escape a just assessment or charge through favor or regard or otherwise.” Failure to subscribe the certificate to the record of assessments and charges, or any certificate, shall not affect the validity of any assessment or charge.