Do a copy of the node to a given document.

def copyNode(self, node, extended):
        """Do a copy of the node to a given document. """
        if node is None: node__o = None
        else: node__o = node._o
        ret = libxml2mod.xmlDocCopyNode(node__o, self._o, extended)
        if ret is None:raise treeError('xmlDocCopyNode() failed')
        __tmp = xmlNode(_obj=ret)
        return __tmp