anchor.diff:  add_new_session_entry(ID,_State) ->
      tts_data:sessions_create_new(ID). 
   
  -lookup_session(ID) ->
  +lookup_session_pid(ID) ->
      tts_data:sessions_get_pid(ID). 
   
   set_session_for_id(ID,Pid) ->
  
positive.code: repeat_id_gen_if_needed(_,_ID,State) ->
      get_unique_id(State).
  
  return_pid_or_error({ok, {_ID, Pid}}) ->
      {ok, Pid};
  return_pid_or_error({error,_} = Error) ->
      Error.
  
  
  %% 
  %% functions with data access
  
negative.code: 
  -spec get_session(ID :: uuid:uuid()) -> {ok, pid()} | {error, not_found}.
  get_session(ID) ->
      lookup_session_pid(ID).
  
  -spec session_closing(ID :: binary()) -> ok.
  session_closing(ID) ->
  