The following DataNodes have no identifier: 3
http://classic.wikipathways.org/instance/WP1015_r117614 http://rdf.wikipathways.org/Pathway/WP1015_r117614/DataNode/b3056 (Fatty Acid metabolism)
http://classic.wikipathways.org/instance/WP1015_r117614 http://rdf.wikipathways.org/Pathway/WP1015_r117614/DataNode/a5c51 (Pyruvate metabolism)
http://classic.wikipathways.org/instance/WP1015_r117614 http://rdf.wikipathways.org/Pathway/WP1015_r117614/DataNode/d9d89 (Sterol biosynthesis)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier