def METHOD_NAME(self, content):
    if len(content) == 0:
        print "Result is empty"
        sys.exit(1)
    xmldoc = parseString(content)
    itemlist = xmldoc.getElementsByTagName('aa')
    if itemlist.length <= 0:
        print "Result is empty"
        sys.exit(1)
    for item in itemlist:
        print "PDB_SITE" + ':' + item.getAttribute("pos") + item.getAttribute("aa") + ';'