how to write this code by ML?

Write a function removeDuplicates that takes a list as input and removes the duplicate values from the list. Each value should appear in the output list only once but the order does not matter. The function should have type ''a list - ''a list Examples: removeDuplicates [1, 5, 1, 3, 4, 3, 51i > removeDuplicates ["a", "e", "c", "a", "a", "b", "c", "d" > removeDuplicatesthis may give a warning) I1