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Movies like Convict 99 (1938)

A disgraced school master, Benjamin Twist, is mistaken for a tough prison governor and assigned the charge of a prison for particularly hardened criminals. Believing he is being sent to a school rather than a prison, he celebrates accordingly only to find that his drunkenness accidently lands him on the wrong side of the prison bars. The Governorship is eventually restored to him, and he sets about popularising himself amongst the convicts by turning a blind eye to their shady dealings.