input: Write a function that swaps the values of two variables and prints their new values.
  def swap_values(x, y):
      x, y = y, x
      print("x:", x)
      print("y:", y)
  
  assert swap_values(5, 10)
  assert swap_values(20, 30)
  assert swap_values(0, -1)
  assert swap_values("a", "b")
output: def swap_values(x, y):
      x, y = y, x
      print("x:", x)
      print("y:", y)