input: def swap_variables(x: int, y: int) -> None:
      """
      Swap the values of two variables and print the new values.
      
      >>> swap_variables(5, 10)
      x: 10
      y: 5
      """
      x, y = y, x
      print("x:", x)
      print("y:", y)
output:     x, y = y, x
      print("x:", x)
      print("y:", y)