Cal. Elec. Code § 6784

Each section shall be prepared with the lines, for signatures numbered, and shall have attached the declaration of the circulator who obtained signatures to it, stating, under penalty of perjury, that she or he is a voter registered as affiliated with the Peace and Freedom Party, that all the signatures to the attached section were made in her or his presence, and that to the best of her or his knowledge and belief each signature to the section is the genuine signature of the person whose name it purports to be. No other declaration is required to be made.