Traversal function for the "descendant-or-self" direction
          the descendant-or-self axis contains the context node and
          the descendants of the context node in document order; thus
          the context node is the first node on the axis, and the
          first child of the context node is the second node on the
           axis

def xpathNextDescendantOrSelf(self, cur):
        """Traversal function for the "descendant-or-self" direction
          the descendant-or-self axis contains the context node and
          the descendants of the context node in document order; thus
          the context node is the first node on the axis, and the
          first child of the context node is the second node on the
           axis """
        if cur is None: cur__o = None
        else: cur__o = cur._o
        ret = libxml2mod.xmlXPathNextDescendantOrSelf(self._o, cur__o)
        if ret is None:raise xpathError('xmlXPathNextDescendantOrSelf() failed')
        __tmp = xmlNode(_obj=ret)
        return __tmp