The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP4940_r124896 http://rdf.wikipathways.org/Pathway/WP4940_r124896/DataNode/b022f (gamma tubulin complex)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier