public static DictionaryCanRepeatKey<TKey, TElement> ToDictionaryCanRepeatKey<TSource, TKey, TElement>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector) => new DictionaryCanRepeatKey<TKey, TElement>(source.Select(x => (keySelector(x), elementSelector(x))).ToArray());
