fact: Definition evalWriterT {T} (c : writerT Monoid_S m T) : m T := bind (runWriterT c) (fun (x : pprod T S) => ret (pfst x)).
imports: ExtLib.Structures.Monads ExtLib.Structures.Monoid ExtLib.Data.PPair ExtLib.Data.Monads.IdentityMonad Coq.Program.Basics