anchor.diff:  	end.
   %% @hidden
   determinate_units([#product{price = Prices}], Type, Flag, Used, Validity, Buckets) ->
  -	case charge(Type, Used, Flag, lists:sort(fun sort_buckets/2, Buckets)) of
  +	case charge(Type, Used, Flag, Buckets) of
   		{Charged, NewBuckets} when Charged < Used ->
   			PriceType = case Type of
   				octets -> usage;
  
positive.code: 		Charged :: integer().
  charge(Type, Charge, Final, Buckets) ->
  	Now = erlang:system_time(?MILLISECOND),
  	charge(Type, Charge, Now, Final, Buckets, [], 0).
  %% @hidden
  charge(Type, Charge, Now, Final, [#bucket{bucket_type = Type,
  		termination_date = T1} | T], Acc, Charged) when T1 =/= undefined, T1 =< Now->
  
negative.code: 			{Charged, [Bucket | NewBuckets]}
  	end.
  
  remove_session(SessionList, [H | T]) ->
  	remove_session1(remove_session(SessionList, T), H);
  remove_session(SessionList, []) ->
  