The following DataNodes have no identifier: 3
http://classic.wikipathways.org/instance/WP1041_r117611 http://rdf.wikipathways.org/Pathway/WP1041_r117611/DataNode/ab1 (APOC1)
http://classic.wikipathways.org/instance/WP1041_r117611 http://rdf.wikipathways.org/Pathway/WP1041_r117611/DataNode/a92 (APOC2)
http://classic.wikipathways.org/instance/WP1041_r117611 http://rdf.wikipathways.org/Pathway/WP1041_r117611/DataNode/f52 (CETP)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier