input: Write a function to reverse a given list. If the list is empty, return an empty list.
  def reverse_list(list):
      return list[::-1]
  assert reverse_list([1, 2, 3, 4, 5])==[5, 4, 3, 2, 1]
  assert reverse_list([])==[]
output: def reverse_list(list):
      return list[::-1]