anchor.diff:          , get_max_nonce/1
           , invalid_txs/2
           , peek/1
  +        , peek/2
           , push/1
           , push/2
           , size/0
  
positive.code:             #state{db = Mempool} = State) ->
      do_top_change(OldHash, NewHash, Mempool),
      {reply, ok, State};
  handle_call({peek, MaxNumberOfTxs}, _From, #state{db = Mempool} = State)
    when is_integer(MaxNumberOfTxs), MaxNumberOfTxs >= 0;
         MaxNumberOfTxs =:= infinity ->
      Txs = pool_db_peek(Mempool, MaxNumberOfTxs),
      {reply, {ok, Txs}, State};
  handle_call({get_candidate, MaxNumberOfTxs, BlockHash}, _From, State) ->
      Txs = int_get_candidate(State, MaxNumberOfTxs, BlockHash),
  
negative.code: %% pool.
  -spec peek(pos_integer() | infinity) -> {ok, [aetx_sign:signed_tx()]}.
  peek(MaxN) when is_integer(MaxN), MaxN >= 0; MaxN =:= infinity ->
      gen_server:call(?SERVER, {peek, MaxN, all}).
  
  %% Only return transactions for a specific account public key
  -spec peek(pos_integer() | infinity, aec_keys:pubkey()) -> 
                                         {ok, [aetx_sign:signed_tx()]}.
  peek(MaxN, Account) when is_integer(MaxN), MaxN >= 0; MaxN =:= infinity ->
      gen_server:call(?SERVER, {peek, MaxN, Account}).
  
  -spec get_candidate(pos_integer(), binary()) -> {ok, [aetx_sign:signed_tx()]}.
  get_candidate(MaxN, BlockHash) when is_integer(MaxN), MaxN >= 0,
  