The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP3150_r117617 http://rdf.wikipathways.org/Pathway/WP3150_r117617/DataNode/ed228 (FMO)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier