anchor.diff:  -module(erl_reader).
   -behaviour(gen_server).
   
  --export([start/0, start_link/0, add_feed/2, import_feed_list/2, list_feeds/0, update/0, update_feed/1]).
  +-export([start/0, start_link/0, add_feed/2, import_feed_list/2]).
   
   -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
   
  
positive.code:         throw:Reason -> {reply, Reason, State}
      end;
  
  handle_call(list, _From, #state{feeds=Feeds}=State) ->
      {reply, get_all_feeds(Feeds), State};
  
  handle_call(update, _From, #state{feeds=Feeds}=State) ->
      check_for_updates(Feeds),
      {reply, ok, State};
  
  handle_call({update_feed, Uri}, _From, #state{feeds=Feeds}=State) ->
      update_feed(Uri, Feeds),
      {reply, ok, State};
  
  handle_call(_, _From, State) ->
      {reply, ok, State}.
  
  
negative.code: 
  init([]) ->
      io:format("~p starting~n", [?MODULE]),
      {ok, #state{}}.
  
  handle_call({add, User, Uri}, _From, #state{feeds=Feeds}=State) ->
  