Cal. Civ. Code § 5950

5950.    (a) At the time of commencement of an enforcement action, the party commencing the action shall file with the initial pleading a certificate stating that one or more of the following conditions are satisfied: (1) Alternative dispute resolution has been completed in compliance with this article. (2) One of the other parties to the dispute did not accept the terms offered for alternative dispute resolution. (3) Preliminary or temporary injunctive relief is necessary. (b) Failure to file a certificate pursuant to subdivision (a) is grounds for a demurrer or a motion to strike unless the court finds that dismissal of the action for failure to comply with this article would result in substantial prejudice to one of the parties.