Do a recursive copy of the node list.

def docCopyNodeList(self, doc):
        """Do a recursive copy of the node list. """
        if doc is None: doc__o = None
        else: doc__o = doc._o
        ret = libxml2mod.xmlDocCopyNodeList(doc__o, self._o)
        if ret is None:raise treeError('xmlDocCopyNodeList() failed')
        __tmp = xmlNode(_obj=ret)
        return __tmp