Non-zero count of metabolites with more than one InChIKey: 1
http://www.wikipathways.org/instance/WP561_rr124939 (example) has: protoporphyrin IX 553-12-8 with InChIKeys: KSFOVUSSGSKXFI-UJJXFSCMSA-N, ZCFFYALKHPIRKJ-UHFFFAOYSA-N