input: Write a python function to swap the values of two variables using a temporary variable.
  assert swap_values(10, 20) == (20, 10)
  assert swap_values(5, 7) == (7, 5)
  assert swap_values(-1, 1) == (1, -1)
output: def swap_values(a, b):
      temp = a
      a = b
      b = temp
      return a, b