What is considered discretion when it comes to discretion?

"Discretion may be defined, when applied to public functionaries, as the power conferred on them by law to act officially according to the dictates of their own judgment. A ministerial act, on the other hand, is one that a public officer is required to perform in a prescribed manner in obedience to the mandate of legal authority and without regard to his own judgment or opinion concerning the propriety or impropriety of the act to be performed, when a given state of fact exists. [Citation.] Stated otherwise, it is ... an act or duty prescribed by some existing law that makes it incumbent on him to perform precisely as laid down by the law." (People ex rel. Fund American Companies v. California Ins. Co. (1974) 43 Cal.App.3d 423, 431, 117 Cal.Rptr. 623.)

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