input: def swap_variables(x: int, y: int) -> tuple:
      """Swap the values of two variables and return them in a tuple.
      >>> swap_variables(5, 10)
      (10, 5)
      >>> swap_variables(0, 15)
      (15, 0)
      """
  
      x, y = y, x
      return x, y
output:     x, y = y, x
      return x, y