code: def xpathNewValueTree(self):
          
          ret = libxml2mod.xmlXPathNewValueTree(self._o)
          if ret is None:raise xpathError('xmlXPathNewValueTree() failed')
          return xpathObjectRet(ret)
docs: Create a new xmlXPathObjectPtr of type Value Tree (XSLT)
             and initialize it with the tree root @val