Cal. Pen. Code § 1551.2
At the initial appearance of a person arrested under Section 1551 or 1551.1, he shall be informed of the reason for his arrest and of his right to demand and procure counsel. If the person denies that he is the same person charged with or convicted of a crime in the other state, a hearing shall be held within 10 days to determine whether there is probable cause to believe that he is the same person and whether he is charged with or convicted of a crime in the other state. At the hearing, the magistrate shall accept a certified copy of an indictment found, an information, a verified complaint, a judgment or sentence, or other judicial proceedings against that person in the state in which the crime is charged or the conviction occurred, and such copy shall constitute conclusive proof of its contents. Witnesses from the other state shall not be required to be present at the hearing.
Ca. Pen. Code § 1551.2