What is the test for a motion to compel a magistrate to reinstate a portion of a dismissed civil action?

3 This statute provides in part: "(a) When an action is dismissed by a magistrate pursuant to Section 859b, 861, 871, 1008, 1381, 1381.5, 1385, 1387, or 1389, or a portion thereof is dismissed pursuant to those same sections which may not be charged by information under the provisions of Section 739, the prosecutor may make a motion in the superior court within 15 days to compel the magistrate to reinstate the complaint or a portion thereof.... [p] (b) Notice of the motion shall be made to the defendant and the magistrate. The only ground for the motion shall be that, as a matter of law, the magistrate erroneously dismissed the action or a portion thereof."

4 Overruled by Landrum v. Superior Court (1981) 30 Cal.3d 1, 177 Cal.Rptr. 325, 634 P.2d 352.