What authority does a judge have to remove a material witness from a state prison?

Penal Code section 2621 states that when a material witness who is a prisoner in a state prison must be brought before a trial court, an order for the prisoner's temporary removal from prison "may" be made by the trial court. The word "may" generally denotes a permissive standard as contrasted with the mandatory nature of the word "shall." (People v. Failla (2006) 140 Cal.App.4th 1514, 1521.) Penal Code section 1567, which also addresses bringing a prisoner in a state prison before a trial court for any proceeding, uses the discretionary word "may" when referencing the authority of the trial court to issue an order.