def mergeStyles(self, styles):
        " XXX Bugfix for use in PISA "
        for k, v in six.iteritems(styles):
            if k in self and self[k]:
                self[k] = copy.copy(self[k])
                self[k].update(v)
            else:
                self[k] = v
XXX Bugfix for use in PISA