Python创建xml的方法

from xml.dom.minidom import Documentclass write_xml(Document):  def __init__(self):    Document.__init__(self)  def set_tag(self,tag):    self.tag = tag    self.tag1 = self.createElement(self.tag)    self.appendChild(self.tag1)    self.maincard = self.createElement("card")    self.maincard.setAttribute("id", "main")    self.maincard.setAttribute("id2","main2")    self.tag1.appendChild(self.maincard)    self.paragraph1 = self.createElement("p")    self.maincard.appendChild(self.paragraph1)    self.ptext = self.createTextNode("This is a test!")    self.paragraph1.appendChild(self.ptext)  def display(self):    print self.toprettyxml(indent="  ")wx = write_xml()wx.set_tag('test')wx.display()