The following DataNodes have no identifier: 4
http://classic.wikipathways.org/instance/WP1283_r106951 http://rdf.wikipathways.org/Pathway/WP1283_r106951/DataNode/e1559 (B15)
http://classic.wikipathways.org/instance/WP1283_r106951 http://rdf.wikipathways.org/Pathway/WP1283_r106951/DataNode/b30f8 (CI-SGDH)
http://classic.wikipathways.org/instance/WP1283_r106951 http://rdf.wikipathways.org/Pathway/WP1283_r106951/DataNode/a43ad (LOC727762)
http://classic.wikipathways.org/instance/WP1283_r106951 http://rdf.wikipathways.org/Pathway/WP1283_r106951/DataNode/ccd3a (NUOMS)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier