The provisions of this chapter shall be construed liberally and no defect or variance in any of the proceedings herein shall vitiate any assessment, unless the owner, before the commencement of the work, points out such defect or variance to the city council and gives the council the opportunity to rectify the same, and no variance or defect occurring after the commencement of the work shall in any way invalidate or vitiate the assessment or lien. (Prior code § 21.04.028)