Convert and return the XML for an *ele* (:class:`~xml.etree.ElementTree.Element`) with specified *encoding*.

def to_xml(ele, encoding="UTF-8", pretty_print=False):
    "Convert and return the XML for an *ele* (:class:`~xml.etree.ElementTree.Element`) with specified *encoding*."
    xml = etree.tostring(ele, encoding=encoding, pretty_print=pretty_print)
    if sys.version < '3':
        return xml if xml.startswith('<?xml') else '<?xml version="1.0" encoding="%s"?>%s' % (encoding, xml)
    else:
        return xml.decode('UTF-8') if xml.startswith(b'<?xml') \
            else '<?xml version="1.0" encoding="%s"?>%s' % (encoding, xml.decode('UTF-8'))