anchor.diff:              ByVal2 = add_key_to_val_idx(Key,Val,ByVal1),
               {ByKey1,ByVal2}
       end.
  +
  +is_empty({ByVal,_ByKey}) ->
  +    gb_trees:is_empty(ByVal).
   
   get_min({ByVal,_ByKey}) ->
       case gb_trees:is_empty(ByVal) of
  
positive.code: -author("Kalin").
  
  %% API
  -export([store/3, get_min/1, remove/2, new/0]).
  
  
  new() ->
  
negative.code:         gb_trees:empty(),   %% A tree of Vals. Each Val can have several keys associated with it
          dict:new()    %% A tree of Keys, Every key has one corresponding Val associated with it
      }.
  
  get_val(Key,{_,ByKey}) ->
      case dict:find(Key,ByKey) of
          error -> none;
          {ok,Val} -> {ok,Val}
      end.
  
  remove(Key,{ByVal,ByKey}) ->
      case dict:find(Key,ByKey) of
  