public int CompareTo(IonMobilityValue other) { if (ReferenceEquals(this, other)) { return(0); } if (ReferenceEquals(null, other)) { return(1); } var valueComparison = Nullable.Compare(Mobility, other.Mobility); if (valueComparison != 0) { return(valueComparison); } return(Units.CompareTo(other.Units)); }