System.Linq.CachedReflectionInfo.GroupBy_TSource_TKey_2 C# (CSharp) Метод

        public static MethodInfo GroupBy_TSource_TKey_2(Type TSource, Type TKey) =>
             (s_GroupBy_TSource_TKey_2 ??
             (s_GroupBy_TSource_TKey_2 = new Func<IQueryable<object>, Expression<Func<object, object>>, IQueryable<IGrouping<object, object>>>(Queryable.GroupBy).GetMethodInfo().GetGenericMethodDefinition()))
              .MakeGenericMethod(TSource, TKey);