input: def swap_variables(x: int, y: int) -> tuple:
      """ Swap the values of two variables.
      >>> swap_variables(5, 10)
      (10, 5)
      >>> swap_variables(8, 4)
      (4, 8)
      """
      x, y = y, x
      return x, y
output:     x, y = y, x
      return x, y