input: Write a python function to remove duplicates from a list.
  assert remove_duplicates([1, 2, 4, 2, 5, 6, 3, 3]) == [1, 2, 3, 4, 5, 6]
  assert remove_duplicates([1, 1, 1, 1, 1]) == [1]
  assert remove_duplicates([5, 3, 4, 3, 5, 2]) == [2, 3, 4, 5]
output: def remove_duplicates(lst):
      return sorted(set(lst))