input: Write a python function to remove duplicates from a list.
  assert remove_dups([1, 2, 2, 3, 4, 4, 5]) == [1, 2, 3, 4, 5]
  assert remove_dups([10, 20, 20, 30, 40, 40, 50]) == [10, 20, 30, 40, 50]
  assert remove_dups([5, 5, 5, 6, 6, 7, 8, 8, 9]) == [5, 6, 7, 8, 9]
output: def remove_dups(lst):
      return list(dict.fromkeys(lst))