public function add_metadata_resource(cc_i_metadata_resource $met, $identifier) {
        $metanode  = $this->node("//imscc:resource".
            "[@identifier='".
            $identifier.
            "']");
        $metanode2 = $this->node("//imscc:resource".
            "[@identifier='".
            $identifier.
            "']/imscc:file");
        $nspaces   = $this->activemanifest->get_cc_namespaces();
        $dnode     = $this->append_new_element_ns($metanode2, $nspaces['imscc'], 'metadata');
        $this->activemanifest->create_metadata_resource_node($met, $this->doc, $dnode);
    }