The following DataNodes have no identifier: 2
http://classic.wikipathways.org/instance/WP1245_r116708 http://rdf.wikipathways.org/Pathway/WP1245_r116708/DataNode/b366d (6-HITC)
http://classic.wikipathways.org/instance/WP1245_r116708 http://rdf.wikipathways.org/Pathway/WP1245_r116708/DataNode/d739f (Caffeic acid phenethyl ester)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier