anchor.diff:      end.
   
   
  +%%--------------------------------------------------------------------
  +%% @doc
  +%% Begin a transaction.
  +%%
  +%% @spec txn_begin() -> ok | {error, Error}
  +%%
  +%% @equiv txn_begin([])
  +%% @see txn_begin/1
  +%% @end
  +%%--------------------------------------------------------------------
   -spec txn_begin() -> ok | db_error().
   
   txn_begin() ->
       txn_begin([]).
   
   
  +%%--------------------------------------------------------------------
  +%% @doc
  +%% Begin a transaction.
  +%%
  +%% @spec txn_begin(Opts) -> ok | {error, Error}
  +%% where
  +%%    Opts = [atom()]
  +%%
  +%% @end
  +%%--------------------------------------------------------------------
   -spec txn_begin(Opts :: db_flags()) -> ok | db_error().
   
   txn_begin(Opts) ->
  
positive.code:     end.
  
  
  -spec txn_commit() -> ok | db_error().
  
  txn_commit() ->
      txn_commit([]).
  
  
  -spec txn_commit(Opts :: db_flags()) -> ok | db_error().
  
  txn_commit(Opts) ->
  
negative.code:     end.
  
  
  %%--------------------------------------------------------------------
  %% @doc
  %% Retrieve a value based on key.
  %%
  %% @spec get_r(Db, Key) -> not_found | {ok, Value}
  %% where
  %%    Db = integer()
  %%    Key = term()
  %%
  %% @throws {error, Error}
  %%
  %% @equiv get_r(Db, Key, [])
  %% @see get_r/3
  %% @end
  %%--------------------------------------------------------------------
  -spec get_r(Db :: db(), Key :: db_key()) ->
      not_found | {ok, db_ret_value()}.
  
  