Converts the inputted set tag to Python.
        
        :param      elem | <xml.etree.ElementTree>
        
        :return     <set>

def load(self, elem):
        """
        Converts the inputted set tag to Python.
        
        :param      elem | <xml.etree.ElementTree>
        
        :return     <set>
        """
        self.testTag(elem, 'set')
        out = set()
        for xitem in elem:
            out.add(XmlDataIO.fromXml(xitem))
        return out