proposition: Lemma callccE (A B : UU0) (f : (A -> M B) -> M A) : callcc f = usual_callcc f.
proof: Proof. by []. Qed.
imports: mathcomp(all_ssreflect) imonae_lib HB(structures) ihierarchy imonad_lib ifail_lib istate_lib itrace_lib imonad_transformer