The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP4292_r128219 http://rdf.wikipathways.org/Pathway/WP4292_r128219/DataNode/b5879 (X-MT)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier