想要创建的xml文件节点属性按照自己输入的顺序排列的可以做以下的修改
将# a_names = sorted(attrs.keys())改成a_names=attrs.keys()

    def writexml(self, writer, indent="", addindent="", newl=""):
    writer.write(indent+"<" + self.tagName)
    attrs = self._get_attributes()
    a_names=attrs.keys()
    # a_names = sorted(attrs.keys())
    for a_name in a_names:
        writer.write(" %s=\"" % a_name)
        _write_data(writer, attrs[a_name].value)
        writer.write("\"")
        writer.write("\n")
    if self.childNodes:
        writer.write(">")
        if (len(self.childNodes) == 1 and
            self.childNodes[0].nodeType == Node.TEXT_NODE):
            self.childNodes[0].writexml(writer, '', '', '')
        else:
            writer.write(newl)
            for node in self.childNodes:
                node.writexml(writer, indent+addindent, addindent, newl)