public static MethodInfo ThenByDescending_TSource_TKey_3(Type TSource, Type TKey) =>
(s_ThenByDescending_TSource_TKey_3 ??
(s_ThenByDescending_TSource_TKey_3 = new Func<IOrderedQueryable<object>, Expression<Func<object, object>>, IComparer<object>, IOrderedQueryable<object>>(Queryable.ThenByDescending).GetMethodInfo().GetGenericMethodDefinition()))
.MakeGenericMethod(TSource, TKey);