Xml Parse

xml的概念可以从html扩展进行理解

关键字：root, tag，element, attr

最后：XML parsing - ElementTree vs SAX and DOM

python解析xml的常用模块如下：

https://docs.python.org/2/library/xml.html#xml-vulnerabilities

import xml.dom.minidom
import xml.etree.ElementTree
import xml.sax
from lxml import etree