Cal. Gov. Code § 68752
If any person refuses to attend or testify or produce any writings or things required by any subpoena, the commission or the masters may petition the superior court for the county in which the hearing is pending for an order compelling the person to attend and testify or produce the writings or things required by the subpoena before the commission or the masters. The court shall order the person to appear before it at a specified time and place and then and there show cause why the person has not attended or testified or produced the writings or things as required. A copy of the order shall be served upon the person. If it appears to the court that the subpoena was regularly issued, the court shall order the person to appear before the commission or the masters at the time and place fixed in the order and testify or produce the required writings or things. Upon failure to obey the order, the person shall be dealt with as for contempt of court.
Ca. Gov. Code § 68752