Python创建xml的方法

from xml.dom.minidom import Document
class 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()