anchor.diff:              {ok, UpdatedFeeds};
           no_match ->
               case supervisor:start_child(er_feed_sup, [Uri]) of
  -                {ok, _ChildPid} -> {ok, Feeds};
  +                {ok, Pid} ->
  +                    UpdatedFeeds = maps:put(Uri, Pid, Feeds),
  +                    {ok, UpdatedFeeds};
                   {error, Error} -> {Error, Feeds}
               end
       end.
  
positive.code: -include("deps/atomizer/src/atomizer.hrl").
  -include("deps/seymour/src/seymour.hrl").
  
  -record(state, {feeds=[]}).
  
  -define(INTERVAL, 5000).
  
  
negative.code: 
  add_user_to_feed(User, Uri, Feeds) ->
      io:format("Attempting to add user ~p to feed ~p~n", [User, Uri]),
      case maps:is_key(Uri, Feeds) of
          true ->
              io:format("Found feed~n", []),
              Feed = maps:get(Uri, Feeds),
              case lists:member(User, Feed#er_feed.users) of
                  true ->
                      io:format("Already subscribed~n", []),
  