input: Write a python function to reverse a list.
  assert reverse_list([10, 20, 30, 40, 50]) == [50, 40, 30, 20, 10]
  assert reverse_list([1, 2, 3, 4, 5]) == [5, 4, 3, 2, 1]
  assert reverse_list([100, 200, 300]) == [300, 200, 100]
output: def reverse_list(lst):
      return lst[::-1]