namespace System { public struct ValueTuple<T1> : IStructuralComparable, IStructuralEquatable, IComparable, IComparable<ValueTuple<T1>>, IEquatable<ValueTuple<T1>> { public T1 Item1; public ValueTuple(T1 item1); public int CompareTo(ValueTuple<T1> other); public bool Equals(ValueTuple<T1> other); } }