anchor.diff:  			Now, lists:reverse(Acc) ++ CentsBuckets, UnitsBuckets, []);
   convert(Price, Type, Size, ServiceId, ChargingKey, SessionId, Now,
   		[#bucket{remain_amount = R, end_date = Expires,
  -		attributes = []} | T], UnitsBuckets, Acc)
  +		attributes = #{bucket_type := normal}} | T], UnitsBuckets, Acc)
   		when R >= 0, Expires /= undefined, Expires =< Now ->
   	convert(Price, Type, Size, ServiceId, ChargingKey, SessionId,
   			Now, T, UnitsBuckets, Acc);
  
positive.code: 
  %% @hidden
  update(Type, Charge, Reserve, Now, ServiceId, ChargingKey, SessionId,
  		[#bucket{end_date = Expires, attributes = [],
  		remain_amount = Remain} | T], Acc, Charged, Reserved)
  		when Expires /= undefined, Expires =< Now, Remain >= 0 ->
  	update(Type, Charge, Reserve, Now,
  
negative.code: 
  %% @hidden
  charge_session1(Type, Charge, Now, ServiceId, ChargingKey, SessionId,
  		[#bucket{end_date = Expires, attributes = #{bucket_type := normal},
  		remain_amount = R} | T], Acc, Charged)
  		when R >= 0, Expires /= undefined, Expires =< Now ->
  	charge_session1(Type, Charge, Now,
  