Traversal function for the "descendant" direction the
          descendant axis contains the descendants of the context
          node in document order; a descendant is a child or a child
           of a child and so on.

def xpathNextDescendant(self, ctxt):
        """Traversal function for the "descendant" direction the
          descendant axis contains the descendants of the context
          node in document order; a descendant is a child or a child
           of a child and so on. """
        if ctxt is None: ctxt__o = None
        else: ctxt__o = ctxt._o
        ret = libxml2mod.xmlXPathNextDescendant(ctxt__o, self._o)
        if ret is None:raise xpathError('xmlXPathNextDescendant() failed')
        __tmp = xmlNode(_obj=ret)
        return __tmp