input: Write a function to swap the values of two variables and return them in the swapped order. The function should take two parameters, the first variable and the second variable. If both variables are the same, it should return them in the same order.
  assert swap_variables(5, 10)==(10, 5)
  assert swap_variables(10, 5)==(5, 10)
  assert swap_variables('a', 'b')==('b', 'a')
  assert swap_variables(5, 5)==(5, 5)
  assert swap_variables([1, 2], [3, 4])==([3, 4], [1, 2])
output: def swap_variables(var1, var2):
      return var2, var1