(a) A municipal code may be amended from time to time by ordinances duly enacted and published as required by law and passed in such form as to indicate the intention of the legislative body of the city to make them a part of the municipal code or revision.
(b)
(1) When so passed, copies of the ordinances shall be inserted in the copies of the municipal code maintained by the city clerk or recorder, and the ordinances are a part of the municipal code and have the same force and effect as if included at the time of the original adoption of the municipal code.
(2) Under this section, an amendment does not give an amended ordinance retroactive effect.