About: http://webisa.webdatacommons.org/284457503

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	It seams to just be defaulting to a new IService (which one hopes throws a compile time exception) if the messageObj is not of type A or B. I would use a collection of allowed types and then return itself if in said collection.
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com