The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP1233_r104968 http://rdf.wikipathways.org/Pathway/WP1233_r104968/DataNode/b30 (POLD1)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier