In People v. Vienne (1973) 30 Cal.App.3d 266, the court rejected attempts to challenge the competency of counsel in the prior proceeding, with the following observation: "It should be obvious that any alleged constitutional infirmity in a prior conviction -- other than the right to counsel -- is a matter which must be left to proceedings in habeas corpus. Otherwise, the hearing on the alleged infirmity of the prior could involve more issues and more trial time than the substantive case itself. For example, the prior conviction will often have arisen in another jurisdiction. To explore matters other than the easily determined fact of representation by, or waiver of, counsel could -- and no doubt would -- require a lengthy recess of the trial in order to procure witnesses and other evidence with the resultant possibility of frequent declaration of mistrials." (30 Cal.App.3d at p. 272.)