input: def swap_values(x: int, y: int):
      """Write a Python program to swap the values of two variables.
      >>> swap_values(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)