| Proof proof -> sequents_viewer#load_logo_with_qed
| No_proof -> sequents_viewer#load_logo
| Intermediate _ -> assert false (* only the engine may be in this state *)
| Proof proof -> sequents_viewer#load_logo_with_qed
| No_proof -> sequents_viewer#load_logo
| Intermediate _ -> assert false (* only the engine may be in this state *)