invalid token 1519 error

[[email protected]]

hello,
I heve the error

public long GetPOCVolume() => ladder.Max(kv => kv.Value);

        public long GetPOCVolume(TradeSide side) => ladderBidAsk[(int). side].Max(kv => kv.Value);

        public long Volume() => ladder.Sum(kv => kv.Value);

        public bool IsEmpty() => ladder.Count == 0;

Invalid token of (,=> and ) in class,struct and interface
am using the 4.5 .net frame work

[NinjaTrader_JessicaP]

Thank you for your question [email protected] . Since => is used in some programming languages (linked documentation publicly available) to mean "then", to clear up ambiguity, most languages use >= to mean "greater than or equal to". If you change your => to >= your code should compile. Please let us know if there are any other ways we can help.