Sts. & Hy. Code, § 5135

The legislative body may elect to agree to purchase, and purchase, out of the general funds of the city or any other funds eligible for such purpose, an assignment of the warrant, assessment and diagram upon delivery thereof to the contractor, pursuant to Section 5375, at the option of the contractor. Any such purchase shall be at the total amount of the several assessments upon the assessment and diagram attached to the warrant. Any such election to purchase an assignment of the warrant, assessment and diagram by the city shall be stated in the resolution of intention and in the invitation for bids. Upon the purchase of such an assignment of the warrant, assessment and diagram by the city, the city shall succeed to all rights and liens of the contractor to collect and to enforce the payment of the assessments and all bonds issued to represent said assessments.