1. Given a list of numbers with some repeated elements, return a new list that every element appears only once. For example, input list: [1,2,2,3,4,4], output: [1,2,3,4]. 2. Return the powers of 2 in the inclusive range [low, high] ('low', 'high' are positive integers). 3. Dene a class with the method functions: (1) insert(value): insert some value to its internal attribute, (2) get max(): get the maximal value, (3) get mode(): get the mode, (4) get mean(): get the mean