This is in SML.

Problem 6 (20 points) The powerset of a set S is defined as the set of all subsets of S (including the empty set). For ezample, the powerset of 1,2) is t1,2, [1), 12),). Write an SML function called powerset 'a list a list list that when given a list representation of a set as input returns its powerset as output Problem 6 (20 points) The powerset of a set S is defined as the set of all subsets of S (including the empty set). For ezample, the powerset of 1,2) is t1,2, [1), 12),). Write an SML function called powerset 'a list a list list that when given a list representation of a set as input returns its powerset as output