def __init__(self, test, default, arguments):
        super(XPathFilter, self).__init__(test, default, arguments)

        if not etree:
            raise errors.InitError("lxml is required for XPath support.")

        try:
            self.xpath = etree.XPath(self.arguments)
        except etree.XPathSyntaxError, ex:
            raise errors.InitError(
                    "Invalid XPath query '%s': %s"  % (self.arguments, ex))
dataset/ETHPy150Open marineam/nagcat/python/nagcat/plugins/filter_xml.py/XPathFilter.__init__/original