The following DataNodes have no identifier: 19
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier
Metabolite can use H₂O instead of H2O: 1
* [http://classic.wikipathways.org/instance/WP1075_r134297](http://classic.wikipathways.org/instance/WP1075_r134297)
More details at https://www.wikipathways.org/WikiPathwaysCurator/UnicodeTests/water