+ (* now remove this musing from the list of musings for client and tutor
+ *)
+ Hashtbl.replace clients client_id
+ (List.filter ((<>) id)
+ (try Hashtbl.find clients client_id with Not_found -> []));
+ Hashtbl.replace tutors tutor_id
+ (List.filter ((<>) id)
+ (try Hashtbl.find tutors tutor_id with Not_found -> []));