input: Write a function to swap the values of two variables. The function should return the swapped values as a tuple. 
  assert swap_variables(5, 10) == (10, 5)
  assert swap_variables(0, 0) == (0, 0)
  assert swap_variables("a", "b") == ("b", "a")
  assert swap_variables(True, False) == (False, True)
  assert swap_variables([1, 2], [3, 4]) == ([3, 4], [1, 2])
output: def swap_variables(a, b):
      return b, a