Projects and proceedings for the levy of special assessments and the issuance of special assessment bonds commenced before the effective date of the city code may be hereafter consummated and completed and special assessments levied and special assessment bonds issued as required or permitted by any statute or other law amended or repealed by 1972 Iowa Acts, ch. 1088, as though such repeal or amendment had not occurred, and the rights, duties, and interests flowing from such projects and proceedings remain valid and enforceable. Without limiting the foregoing, projects commenced prior to said effective date may be financed by the issuance of special assessment bonds and other bonds under any such amended or repealed law or by the issuance of special assessment bonds, or other bonds under the city code. For the purposes of this section, commencement of a project includes but is not limited to action taken by the council or authorized officer to fix a date for a hearing in connection with any part of a public improvement, and commencement of proceedings for the levy of special assessments and the issuance of special assessment bonds includes but is not limited to action taken by the council to fix a date for a hearing in connection with any public improvement proposed to be financed in whole or in part through special assessments.