namespace System.Runtime.CompilerServices
{
    public sealed class ConditionalWeakTable<TKey, TValue> : IEnumerable, IEnumerable<KeyValuePair<TKey!, TValue!>>
        where TKey, class
        where TValue, class
    {
        public TValue! GetOrAdd<TArg>(TKey! key, Func<TKey!, TArg, TValue!>! valueFactory, TArg factoryArgument);
    }
}