The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP3935_r118425 http://rdf.wikipathways.org/Pathway/WP3935_r118425/DataNode/f4c5b (Irs3)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier