(string-downcase "alphaBETA")
    → "alphabeta"
(string-upcase "alphaBETA")
    → "ALPHABETA"
(string-titlecase "alphaBETA")
    → "Alphabeta"
(string-randcase "alphaBETA")
    → "alphaBEtA"
(string-randcase "alphaBETA")
    → "AlPHaBeTA"