The following DataNodes have no identifier: 4
http://classic.wikipathways.org/instance/WP4162_r129256 http://rdf.wikipathways.org/Pathway/WP4162_r129256/DataNode/d5bb3 (D-alanyl)
http://classic.wikipathways.org/instance/WP4162_r129256 http://rdf.wikipathways.org/Pathway/WP4162_r129256/DataNode/f6e83 (UDP-N-acetyl-D-glucosamine biosynthesis I)
http://classic.wikipathways.org/instance/WP4162_r129256 http://rdf.wikipathways.org/Pathway/WP4162_r129256/DataNode/d15e6 (a D-alanyl-carrier protein)
http://classic.wikipathways.org/instance/WP4162_r129256 http://rdf.wikipathways.org/Pathway/WP4162_r129256/DataNode/d56ff (a D-alanyl-carrier protein)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier