def prettify(self, elem):
        """
            Return a pretty-printed XML string for the Element.
        """
        rough_string = ElementTree.tostring(elem, 'utf8')
        root = etree.fromstring(rough_string)
        return etree.tostring(root, pretty_print=True, encoding=ENCODE_METHOD).replace("  ".encode(), "\t".encode())
        # minidom does not support UTF-8
        '''reparsed = minidom.parseString(rough_string)
        return reparsed.toprettyxml(indent="\t", encoding=ENCODE_METHOD)'''
Return a pretty-printed XML string for the Element.