def parse_content(self, content):
        """
        All child classes inherit this function to parse XML file automatically.
        It will call the function :func:`parse_dom` by default to
        parser all necessary data to :attr:`data` and the :attr:`xmlns` (the
        default namespace) is ready for this function.
        """
        self.dom = self.xmlns = None
        self.data = {}
        # ignore empty xml file
        if len(content) > 3:
            self.raw = '\n'.join(content)
            self.dom = ET.fromstring(self.raw)
            self.xmlns = self.dom.tag.strip("{").split("}")[0] if all(c in self.dom.tag for c in ["{", "}"]) else ""
            self.data = self.parse_dom()