rm __call__ from MathSet and PowerSet
rm __call__ from MathSet and PowerSet

because builtin set is not callable, and callable label types signify symbolic semantics.
Instea create a new list from the object's iterator
tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control