input: Write a function to reverse a list of numbers.
  assert reverse_list([1, 2, 3, 4, 5, 6]) == [6, 5, 4, 3, 2, 1]
  assert reverse_list([10, 20, 30, 40]) == [40, 30, 20, 10]
  assert reverse_list([5, 7, 9, 8, 6, 4, 3]) == [3, 4, 6, 8, 9, 7, 5]
output: def reverse_list(numbers):
      return numbers[::-1]