namespace System { public struct ValueTuple<T1, T2, T3, T4> : IStructuralComparable, IStructuralEquatable, IComparable, IComparable<(T1, T2, T3, T4)>, IEquatable<(T1, T2, T3, T4)> { public T1 Item1; public T2 Item2; public T3 Item3; public T4 Item4; public ValueTuple(T1 item1, T2 item2, T3 item3, T4 item4); public int CompareTo((T1, T2, T3, T4) other); public bool Equals((T1, T2, T3, T4) other); } }