The following DataNodes have no identifier: 2
http://classic.wikipathways.org/instance/WP1259_r124798 http://rdf.wikipathways.org/Pathway/WP1259_r124798/DataNode/a29e9 (ARAT)
http://classic.wikipathways.org/instance/WP1259_r124798 http://rdf.wikipathways.org/Pathway/WP1259_r124798/DataNode/b67a1 (MAPK)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier