No person, firm or corporation shall exercise any franchise mentioned in this chapter in the city except insofar as such person, firm, or corporation may be entitled to do so by direct authority of the Constitution of the state of California or of the United States, unless such person, firm, or corporation shall have obtained a grant therefor in accordance with the provisions of this chapter. Nothing contained in this chapter shall be construed to invalidate any lawful franchise heretofore granted nor to necessitate the obtaining of a new franchise for a use for which a franchise holder shall have a valid unexpired franchise. (Ord. 2000-017 § 2(j) (Exh. A))