anchor.diff:  %%
   %% @end
   %%--------------------------------------------------------------------
  --spec get_data_dirs() -> [db_name(),...] | db_error().
  +-spec get_data_dirs() -> [string()] | db_error().
   
   get_data_dirs() ->
       % Call into the BDB library and get a list of configured data directories
  
positive.code: %% @end
  %%--------------------------------------------------------------------
  -spec update(Db :: db(), Key :: db_key(), Fun :: db_update_fun(), Args :: db_update_fun_args()) ->
      {ok, db_value()} | db_error().
  
  update(Db, Key, Fun, Args) ->
      update(Db, Key, Fun, Args, []).
  
negative.code: %% @end
  %%--------------------------------------------------------------------
  -spec update(Db :: db(), Key :: db_key(), Fun :: db_update_fun()) ->
      {ok, db_value()} | db_txn_error().
  
  update(Db, Key, Fun) ->
      update(Db, Key, Fun, undefined, []).
  