The following DataNodes have no identifier: 2
http://classic.wikipathways.org/instance/WP3140_r117554 http://rdf.wikipathways.org/Pathway/WP3140_r117554/DataNode/d2d75 (RNA polymerase II)
http://classic.wikipathways.org/instance/WP3140_r117554 http://rdf.wikipathways.org/Pathway/WP3140_r117554/DataNode/acaf7 (pri-miRNAs)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier