anchor.diff:                                   end
                            end, [], DB),
       %% see HINT in foldl/3
  -    lists:foldr(Fun, Acc, Data).
  +    lists:foldl(Fun, Acc, Data).
   
   %% @doc foldr iterates over DB and applies Fun(Entry, AccIn) to every element
   %%      encountered in Interval. On the first call AccIn == Acc0. The iteration
  
positive.code:                                  end
                           end, [], DB),
      %% see HINT in foldl/3
      lists:foldl(Fun, Acc, Data).
  
  %% @doc foldl iterates over DB and applies Fun(Entry, AccIn) to every element
  %%      encountered in Interval. On the first call AccIn == Acc0. The iteration
  
negative.code:                               end
                        end, {MaxNum, []}, DB),
      %% see HINT in foldl/3
      lists:foldr(Fun, Acc, Data).
  
  %% @doc makes a foldr over the whole dataset.
  %%      Returns a potentially larger-than-memory dataset. Use with care.
  