anchor.diff:  -spec new(DBName::nonempty_string()) -> db().
   new(_DBName) ->
       Dir = util:make_filename(atom_to_list(node())),
  -    FullDir = lists:flatten([config:read(db_directory), "/", Dir]),
  +    FullDir = [config:read(db_directory), "/", Dir],
       _ = case file:make_dir(FullDir) of
           ok -> ok;
           {error, eexist} -> ok;
  -        {error, Error} -> exit({db_toke, 'cannot create dir', FullDir, Error})
  +        {error, Error} -> erlang:exit({db_toke, 'cannot create dir', FullDir, Error})
       end,
       {_Now_Ms, _Now_s, Now_us} = Now = erlang:now(),
       {{Year, Month, Day}, {Hour, Minute, Second}} =
  -                                                   calendar:now_to_local_time(Now),
  +        calendar:now_to_local_time(Now),
       FileBaseName = util:make_filename(
  -            io_lib:format("db_~B~B~B-~B~B~B\.~B.tch",
  -                          [Year, Month, Day, Hour, Minute, Second, Now_us])),
  +                     io_lib:format("db_~B~B~B-~B~B~B\.~B.tch",
  +                                   [Year, Month, Day, Hour, Minute, Second, Now_us])),
       FullFileName = lists:flatten([FullDir, "/", FileBaseName]),
       new_db(FullFileName, [read, write, create, truncate]).
   
  
positive.code: %% @doc Deletes the tuple saved under Key and returns the new DB.
  %%      If such a tuple does not exists nothing is changed.
  -spec delete(DB::db(), Key::key()) -> db().
  delete({DB, FileName}, Key) ->
      toke_drv:delete(DB, ?IN(Key)),
      {DB, FileName}.
  
  %% @doc Returns the name of the DB specified in new/1.
  -spec get_name(DB::db()) -> nonempty_string().
  
negative.code: %% @doc Saves arbitrary tuple Entry in DB DBName and returns the new DB.
  %%      The key is expected to be the first element of Entry.
  -spec put(DB::db(), Entry::entry()) -> db().
  put({DB, _FileName} = State, Entry) ->
      toke_drv:insert(DB, ?IN(element(1, Entry)), ?IN(Entry)),
      State.
  
  %% @doc Returns the entry that corresponds to Key or {} if no such tuple exists.
  -spec get(DB::db(), Key::key()) -> entry() | {}.
  