这是我的进出口商品

-import(calling, [create_receiver_process/1, create_senders_process/1]).
-export([main/1, read_file/1, merge_method/1, merge_method/2, master_process/1, print_data/1]).

这是我怀疑的代码，是导致错误

{gotintro, Sender, Receiver, Time} ->
            io:format("~p received intro message from ~p [~p]~n", [Receiver, Sender, Time]),
            master_process(RPs);        

        {gotreply, Sender, Receiver, Time} ->
            io:format("~p received reply message from ~p [~p]~n", [ Sender,Receiver, Time]),
            master_process(RPs)

这就是错误，我得到了

=ERROR REPORT==== 14-Jun-2020::20:58:23.841027 ===
Error in process <0.88.0> with exit value:
{undef,[{test,base_receiver_method,[],[]}]}

=ERROR REPORT==== 14-Jun-2020::20:58:23.848795 ===
Error in process <0.100.0> with exit value:
{undef,[{test,send_message,[john,joe],[]}]}

下面是base_receiver_method

base_receiver_method() ->
    receive
        {intro , Sender, Receiver, Time} ->
            io:format("Message Intro ~p ~p~n", [Sender, Receiver]),
            Name = string:concat(lists:flatten(io_lib:format("~p", [Sender])), "sender"),
            N = list_to_atom(Name),
            N ! {reply, Receiver, Sender, Time},
            timer:sleep(round(rand:uniform() * 100)),
            master ! {gotintro, Receiver, Sender, Time},
            base_receiver_method();
        {reply , Sender, Receiver, Time} ->
            io:format("Message Reply ~p ~p~n", [Sender, Receiver]),
            timer:sleep(round(rand:uniform() * 100)),
            master ! {gotreply, Receiver,Sender, Time},
            base_receiver_method()
    after 1000 ->
        exit("Time Up")
    end.

下面是send_message：

send_message(S, R) ->
    Name = string:concat(lists:flatten(io_lib:format("~p", [R])), "receiver"),
    N = list_to_atom(Name),
    {_, _, Time} = erlang:now(),
    N ! {intro, S, R, Time}.