The description of the symmetric difference operation implies that it cannot be applied to more than two sets (http://docs.python.org/3/library/stdtypes.html#set.symmetric_difference).

However, this is certainly possible:

>>> s={1,2}
>>> t={2,3}
>>> u={3,4}
>>> s^t^u
{1, 4}
>>> s.symmetric_difference(t).symmetric_difference(u)
{1, 4}

I am not sure how much of a "semantic" sense that makes, given that symmetric difference is by definition for two sets. (http://en.wikipedia.org/wiki/Symmetric_difference).

So, either the operator should be fixed to allow only two sets or the description be updated.