The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP1423_r124472 http://rdf.wikipathways.org/Pathway/WP1423_r124472/DataNode/c51bd (Gal-GlcNAc-GM1b)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier