Set the root element of the document (doc->children is a
           list containing possibly comments, PIs, etc ...).

def docSetRootElement(self, doc):
        """Set the root element of the document (doc->children is a
           list containing possibly comments, PIs, etc ...). """
        if doc is None: doc__o = None
        else: doc__o = doc._o
        ret = libxml2mod.xmlDocSetRootElement(doc__o, self._o)
        if ret is None:return None
        __tmp = xmlNode(_obj=ret)
        return __tmp