anchor.diff:  
   -export([
            get/0,
  -         check/2
  +         check/2,
  +         create/1,
  +         update/1,
  +         delete/1
           ]).
   
   
  
positive.code: get() ->
      gen_server:call(?SERVER, {get}).
  
  
  -spec(check(Email :: string(), Password :: string()) -> {ok, Rec :: #user{}} | {error, string()}).
  check(Email, Password) ->
  
negative.code:              {stop, Reason :: term(), NewState :: #state{}}).
  handle_call({get}, _From, State) ->
      do_get_users(State);
  handle_call({create, User}, _From, State) ->
    do_create_user(State, User);
  handle_call({update, User}, _From, State) ->
    do_update_user(State, User);
  handle_call({delete, User}, _From, State) ->
    do_delete_user(State, User);
  handle_call({check, Email, Password}, _From, State) ->
      do_check_user(State, Email, Password);
  handle_call(_Request, _From, State) ->
  