The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP4804_r128524 http://rdf.wikipathways.org/Pathway/WP4804_r128524/DataNode/e64c8 (Metabolite)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier