The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP5194_r122165 http://rdf.wikipathways.org/Pathway/WP5194_r122165/DataNode/a9324 (S1P lyase)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier