code: def addChild(self, cur):
          
          if cur is None: cur__o = None
          else: cur__o = cur._o
          ret = libxml2mod.xmlAddChild(self._o, cur__o)
          if ret is None:raise treeError('xmlAddChild() failed')
          __tmp = xmlNode(_obj=ret)
          return __tmp
docs: Add a new node to @parent, at the end of the child (or
            property) list merging adjacent TEXT nodes (in which case
            @cur is freed) If the new node is ATTRIBUTE, it is added
            into properties instead of children. If there is an
             attribute with equal name, it is first destroyed.