private void CheckLapNumbersAreEqual(PostedTime s1, PostedTime s2, PostedTime s3, PostedTime lap) { int lapNumber = (s1 ?? s2 ?? s3 ?? lap).LapNumber; CheckLapNumber(s1, lapNumber, "s1"); CheckLapNumber(s2, lapNumber, "s2"); CheckLapNumber(s3, lapNumber, "s3"); CheckLapNumber(lap, lapNumber, "lap"); }