:1:1: Not in scope: ‘nubBy’ :1:1: Not in scope: ‘nub’ :1:1: Not in scope: ‘nubBy’ :1:1: Not in scope: ‘nub’ :1:1: Not in scope: ‘nub’ Perhaps you meant ‘L.nub’ (imported from Data.List) :1:1: Not in scope: ‘L.nub’ :1:1: Not in scope: ‘nub’