'Get the I{type} qualified reference to the referenced xsd type.
This method takes into account simple types defined through
restriction with are detected by determining that self is simple
(len=0) and by finding a restriction child.
@return: The I{type} qualified reference.
@rtype: qref'

def qref(self):

    qref = self.type
    if ((qref is None) and (len(self) == 0)):
        ls = []
        m = RestrictionMatcher()
        finder = NodeFinder(m, 1)
        finder.find(self, ls)
        if len(ls):
            return ls[0].ref
    return qref
