When any proceeding is initiated under this division by a legislative body other than that of a city or county, and before the resolution of intention is adopted, the proposed resolution, together with a plat or map which shall indicate by a boundary line the extent of territory included in the proposed district, shall be submitted for approval of the legislative body of the city, where the land to be assessed lies within the corporate limits of any city, or of the county, where the land to be assessed lies within an unincorporated territory. When such approval has been secured, the resolution of intention may be adopted and the legislative body initiating the proceeding may thereafter take each and every step required for or suitable for the consummation of the work and the levying, collecting and enforcement of the assessments to cover the expenses thereof and the issuance and enforcement of bonds to represent unpaid assessments.