// This file contains auto-generated code.
// Generated from `System.Linq, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a`.
namespace System
{
    namespace Linq
    {
        public static class Enumerable
        {
            public static TSource Aggregate<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TSource, TSource> func) => throw null;
            public static TAccumulate Aggregate<TSource, TAccumulate>(this System.Collections.Generic.IEnumerable<TSource> source, TAccumulate seed, System.Func<TAccumulate, TSource, TAccumulate> func) => throw null;
            public static TResult Aggregate<TSource, TAccumulate, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, TAccumulate seed, System.Func<TAccumulate, TSource, TAccumulate> func, System.Func<TAccumulate, TResult> resultSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, TAccumulate>> AggregateBy<TSource, TKey, TAccumulate>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, TAccumulate seed, System.Func<TAccumulate, TSource, TAccumulate> func, System.Collections.Generic.IEqualityComparer<TKey> keyComparer = default(System.Collections.Generic.IEqualityComparer<TKey>)) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, TAccumulate>> AggregateBy<TSource, TKey, TAccumulate>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TKey, TAccumulate> seedSelector, System.Func<TAccumulate, TSource, TAccumulate> func, System.Collections.Generic.IEqualityComparer<TKey> keyComparer = default(System.Collections.Generic.IEqualityComparer<TKey>)) => throw null;
            public static bool All<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static bool Any<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static bool Any<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Append<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource element) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> AsEnumerable<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static decimal Average(this System.Collections.Generic.IEnumerable<decimal> source) => throw null;
            public static double Average(this System.Collections.Generic.IEnumerable<double> source) => throw null;
            public static double Average(this System.Collections.Generic.IEnumerable<int> source) => throw null;
            public static double Average(this System.Collections.Generic.IEnumerable<long> source) => throw null;
            public static decimal? Average(this System.Collections.Generic.IEnumerable<decimal?> source) => throw null;
            public static double? Average(this System.Collections.Generic.IEnumerable<double?> source) => throw null;
            public static double? Average(this System.Collections.Generic.IEnumerable<int?> source) => throw null;
            public static double? Average(this System.Collections.Generic.IEnumerable<long?> source) => throw null;
            public static float? Average(this System.Collections.Generic.IEnumerable<float?> source) => throw null;
            public static float Average(this System.Collections.Generic.IEnumerable<float> source) => throw null;
            public static decimal Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal> selector) => throw null;
            public static double Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double> selector) => throw null;
            public static double Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int> selector) => throw null;
            public static double Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long> selector) => throw null;
            public static decimal? Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal?> selector) => throw null;
            public static double? Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double?> selector) => throw null;
            public static double? Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int?> selector) => throw null;
            public static double? Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long?> selector) => throw null;
            public static float? Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float?> selector) => throw null;
            public static float Average<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float> selector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Cast<TResult>(this System.Collections.IEnumerable source) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource[]> Chunk<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int size) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Concat<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) => throw null;
            public static bool Contains<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource value) => throw null;
            public static bool Contains<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource value, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static int Count<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static int Count<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, int>> CountBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> keyComparer = default(System.Collections.Generic.IEqualityComparer<TKey>)) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> DefaultIfEmpty<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> DefaultIfEmpty<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource defaultValue) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Distinct<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Distinct<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> DistinctBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> DistinctBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static TSource ElementAt<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Index index) => throw null;
            public static TSource ElementAt<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int index) => throw null;
            public static TSource ElementAtOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Index index) => throw null;
            public static TSource ElementAtOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int index) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Empty<TResult>() => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Except<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Except<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> ExceptBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TKey> second, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> ExceptBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TKey> second, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static TSource First<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource First<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static TSource FirstOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource FirstOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource defaultValue) => throw null;
            public static TSource FirstOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static TSource FirstOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate, TSource defaultValue) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Linq.IGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Linq.IGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Linq.IGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<System.Linq.IGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> GroupBy<TSource, TKey, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TKey, System.Collections.Generic.IEnumerable<TSource>, TResult> resultSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> GroupBy<TSource, TKey, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TKey, System.Collections.Generic.IEnumerable<TSource>, TResult> resultSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector, System.Func<TKey, System.Collections.Generic.IEnumerable<TElement>, TResult> resultSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector, System.Func<TKey, System.Collections.Generic.IEnumerable<TElement>, TResult> resultSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> GroupJoin<TOuter, TInner, TKey, TResult>(this System.Collections.Generic.IEnumerable<TOuter> outer, System.Collections.Generic.IEnumerable<TInner> inner, System.Func<TOuter, TKey> outerKeySelector, System.Func<TInner, TKey> innerKeySelector, System.Func<TOuter, System.Collections.Generic.IEnumerable<TInner>, TResult> resultSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> GroupJoin<TOuter, TInner, TKey, TResult>(this System.Collections.Generic.IEnumerable<TOuter> outer, System.Collections.Generic.IEnumerable<TInner> inner, System.Func<TOuter, TKey> outerKeySelector, System.Func<TInner, TKey> innerKeySelector, System.Func<TOuter, System.Collections.Generic.IEnumerable<TInner>, TResult> resultSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<(int Index, TSource Item)> Index<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Intersect<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Intersect<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> IntersectBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TKey> second, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> IntersectBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TKey> second, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Join<TOuter, TInner, TKey, TResult>(this System.Collections.Generic.IEnumerable<TOuter> outer, System.Collections.Generic.IEnumerable<TInner> inner, System.Func<TOuter, TKey> outerKeySelector, System.Func<TInner, TKey> innerKeySelector, System.Func<TOuter, TInner, TResult> resultSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Join<TOuter, TInner, TKey, TResult>(this System.Collections.Generic.IEnumerable<TOuter> outer, System.Collections.Generic.IEnumerable<TInner> inner, System.Func<TOuter, TKey> outerKeySelector, System.Func<TInner, TKey> innerKeySelector, System.Func<TOuter, TInner, TResult> resultSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static TSource Last<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource Last<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource defaultValue) => throw null;
            public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate, TSource defaultValue) => throw null;
            public static long LongCount<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static long LongCount<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static decimal Max(this System.Collections.Generic.IEnumerable<decimal> source) => throw null;
            public static double Max(this System.Collections.Generic.IEnumerable<double> source) => throw null;
            public static int Max(this System.Collections.Generic.IEnumerable<int> source) => throw null;
            public static long Max(this System.Collections.Generic.IEnumerable<long> source) => throw null;
            public static decimal? Max(this System.Collections.Generic.IEnumerable<decimal?> source) => throw null;
            public static double? Max(this System.Collections.Generic.IEnumerable<double?> source) => throw null;
            public static int? Max(this System.Collections.Generic.IEnumerable<int?> source) => throw null;
            public static long? Max(this System.Collections.Generic.IEnumerable<long?> source) => throw null;
            public static float? Max(this System.Collections.Generic.IEnumerable<float?> source) => throw null;
            public static float Max(this System.Collections.Generic.IEnumerable<float> source) => throw null;
            public static TSource Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Collections.Generic.IComparer<TSource> comparer) => throw null;
            public static decimal Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal> selector) => throw null;
            public static double Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double> selector) => throw null;
            public static int Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int> selector) => throw null;
            public static long Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long> selector) => throw null;
            public static decimal? Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal?> selector) => throw null;
            public static double? Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double?> selector) => throw null;
            public static int? Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int?> selector) => throw null;
            public static long? Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long?> selector) => throw null;
            public static float? Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float?> selector) => throw null;
            public static float Max<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float> selector) => throw null;
            public static TResult Max<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TResult> selector) => throw null;
            public static TSource MaxBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static TSource MaxBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer) => throw null;
            public static decimal Min(this System.Collections.Generic.IEnumerable<decimal> source) => throw null;
            public static double Min(this System.Collections.Generic.IEnumerable<double> source) => throw null;
            public static int Min(this System.Collections.Generic.IEnumerable<int> source) => throw null;
            public static long Min(this System.Collections.Generic.IEnumerable<long> source) => throw null;
            public static decimal? Min(this System.Collections.Generic.IEnumerable<decimal?> source) => throw null;
            public static double? Min(this System.Collections.Generic.IEnumerable<double?> source) => throw null;
            public static int? Min(this System.Collections.Generic.IEnumerable<int?> source) => throw null;
            public static long? Min(this System.Collections.Generic.IEnumerable<long?> source) => throw null;
            public static float? Min(this System.Collections.Generic.IEnumerable<float?> source) => throw null;
            public static float Min(this System.Collections.Generic.IEnumerable<float> source) => throw null;
            public static TSource Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Collections.Generic.IComparer<TSource> comparer) => throw null;
            public static decimal Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal> selector) => throw null;
            public static double Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double> selector) => throw null;
            public static int Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int> selector) => throw null;
            public static long Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long> selector) => throw null;
            public static decimal? Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal?> selector) => throw null;
            public static double? Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double?> selector) => throw null;
            public static int? Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int?> selector) => throw null;
            public static long? Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long?> selector) => throw null;
            public static float? Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float?> selector) => throw null;
            public static float Min<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float> selector) => throw null;
            public static TResult Min<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TResult> selector) => throw null;
            public static TSource MinBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static TSource MinBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> OfType<TResult>(this System.Collections.IEnumerable source) => throw null;
            public static System.Linq.IOrderedEnumerable<T> Order<T>(this System.Collections.Generic.IEnumerable<T> source) => throw null;
            public static System.Linq.IOrderedEnumerable<T> Order<T>(this System.Collections.Generic.IEnumerable<T> source, System.Collections.Generic.IComparer<T> comparer) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> OrderBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> OrderBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> OrderByDescending<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> OrderByDescending<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer) => throw null;
            public static System.Linq.IOrderedEnumerable<T> OrderDescending<T>(this System.Collections.Generic.IEnumerable<T> source) => throw null;
            public static System.Linq.IOrderedEnumerable<T> OrderDescending<T>(this System.Collections.Generic.IEnumerable<T> source, System.Collections.Generic.IComparer<T> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Prepend<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource element) => throw null;
            public static System.Collections.Generic.IEnumerable<int> Range(int start, int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Repeat<TResult>(TResult element, int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Reverse<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Select<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int, TResult> selector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Select<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TResult> selector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> SelectMany<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, System.Collections.Generic.IEnumerable<TResult>> selector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> SelectMany<TSource, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int, System.Collections.Generic.IEnumerable<TResult>> selector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> SelectMany<TSource, TCollection, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, System.Collections.Generic.IEnumerable<TCollection>> collectionSelector, System.Func<TSource, TCollection, TResult> resultSelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> SelectMany<TSource, TCollection, TResult>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int, System.Collections.Generic.IEnumerable<TCollection>> collectionSelector, System.Func<TSource, TCollection, TResult> resultSelector) => throw null;
            public static bool SequenceEqual<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) => throw null;
            public static bool SequenceEqual<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static TSource Single<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource Single<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static TSource SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static TSource SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource defaultValue) => throw null;
            public static TSource SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static TSource SingleOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate, TSource defaultValue) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Skip<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> SkipLast<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> SkipWhile<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> SkipWhile<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int, bool> predicate) => throw null;
            public static decimal Sum(this System.Collections.Generic.IEnumerable<decimal> source) => throw null;
            public static double Sum(this System.Collections.Generic.IEnumerable<double> source) => throw null;
            public static int Sum(this System.Collections.Generic.IEnumerable<int> source) => throw null;
            public static long Sum(this System.Collections.Generic.IEnumerable<long> source) => throw null;
            public static decimal? Sum(this System.Collections.Generic.IEnumerable<decimal?> source) => throw null;
            public static double? Sum(this System.Collections.Generic.IEnumerable<double?> source) => throw null;
            public static int? Sum(this System.Collections.Generic.IEnumerable<int?> source) => throw null;
            public static long? Sum(this System.Collections.Generic.IEnumerable<long?> source) => throw null;
            public static float? Sum(this System.Collections.Generic.IEnumerable<float?> source) => throw null;
            public static float Sum(this System.Collections.Generic.IEnumerable<float> source) => throw null;
            public static decimal Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal> selector) => throw null;
            public static double Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double> selector) => throw null;
            public static int Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int> selector) => throw null;
            public static long Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long> selector) => throw null;
            public static decimal? Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, decimal?> selector) => throw null;
            public static double? Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, double?> selector) => throw null;
            public static int? Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int?> selector) => throw null;
            public static long? Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, long?> selector) => throw null;
            public static float? Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float?> selector) => throw null;
            public static float Sum<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, float> selector) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Take<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Take<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Range range) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> TakeLast<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> TakeWhile<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> TakeWhile<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int, bool> predicate) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> ThenBy<TSource, TKey>(this System.Linq.IOrderedEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> ThenBy<TSource, TKey>(this System.Linq.IOrderedEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> ThenByDescending<TSource, TKey>(this System.Linq.IOrderedEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Linq.IOrderedEnumerable<TSource> ThenByDescending<TSource, TKey>(this System.Linq.IOrderedEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer) => throw null;
            public static TSource[] ToArray<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, TValue>> source) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, TValue>> source, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this System.Collections.Generic.IEnumerable<(TKey Key, TValue Value)> source) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this System.Collections.Generic.IEnumerable<(TKey Key, TValue Value)> source, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TSource> ToDictionary<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TSource> ToDictionary<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector) => throw null;
            public static System.Collections.Generic.Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.HashSet<TSource> ToHashSet<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Collections.Generic.HashSet<TSource> ToHashSet<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static System.Collections.Generic.List<TSource> ToList<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) => throw null;
            public static System.Linq.ILookup<TKey, TSource> ToLookup<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Linq.ILookup<TKey, TSource> ToLookup<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Linq.ILookup<TKey, TElement> ToLookup<TSource, TKey, TElement>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector) => throw null;
            public static System.Linq.ILookup<TKey, TElement> ToLookup<TSource, TKey, TElement>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TElement> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static bool TryGetNonEnumeratedCount<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, out int count) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Union<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Union<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> UnionBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Func<TSource, TKey> keySelector) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> UnionBy<TSource, TKey>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Func<TSource, TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Where<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, bool> predicate) => throw null;
            public static System.Collections.Generic.IEnumerable<TSource> Where<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, int, bool> predicate) => throw null;
            public static System.Collections.Generic.IEnumerable<(TFirst First, TSecond Second)> Zip<TFirst, TSecond>(this System.Collections.Generic.IEnumerable<TFirst> first, System.Collections.Generic.IEnumerable<TSecond> second) => throw null;
            public static System.Collections.Generic.IEnumerable<(TFirst First, TSecond Second, TThird Third)> Zip<TFirst, TSecond, TThird>(this System.Collections.Generic.IEnumerable<TFirst> first, System.Collections.Generic.IEnumerable<TSecond> second, System.Collections.Generic.IEnumerable<TThird> third) => throw null;
            public static System.Collections.Generic.IEnumerable<TResult> Zip<TFirst, TSecond, TResult>(this System.Collections.Generic.IEnumerable<TFirst> first, System.Collections.Generic.IEnumerable<TSecond> second, System.Func<TFirst, TSecond, TResult> resultSelector) => throw null;
        }
        public interface IGrouping<TKey, TElement> : System.Collections.Generic.IEnumerable<TElement>, System.Collections.IEnumerable
        {
            TKey Key { get; }
        }
        public interface ILookup<TKey, TElement> : System.Collections.Generic.IEnumerable<System.Linq.IGrouping<TKey, TElement>>, System.Collections.IEnumerable
        {
            bool Contains(TKey key);
            int Count { get; }
            System.Collections.Generic.IEnumerable<TElement> this[TKey key] { get; }
        }
        public interface IOrderedEnumerable<TElement> : System.Collections.Generic.IEnumerable<TElement>, System.Collections.IEnumerable
        {
            System.Linq.IOrderedEnumerable<TElement> CreateOrderedEnumerable<TKey>(System.Func<TElement, TKey> keySelector, System.Collections.Generic.IComparer<TKey> comparer, bool descending);
        }
        public class Lookup<TKey, TElement> : System.Collections.Generic.IEnumerable<System.Linq.IGrouping<TKey, TElement>>, System.Collections.IEnumerable, System.Linq.ILookup<TKey, TElement>
        {
            public System.Collections.Generic.IEnumerable<TResult> ApplyResultSelector<TResult>(System.Func<TKey, System.Collections.Generic.IEnumerable<TElement>, TResult> resultSelector) => throw null;
            public bool Contains(TKey key) => throw null;
            public int Count { get => throw null; }
            public System.Collections.Generic.IEnumerator<System.Linq.IGrouping<TKey, TElement>> GetEnumerator() => throw null;
            System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() => throw null;
            public System.Collections.Generic.IEnumerable<TElement> this[TKey key] { get => throw null; }
        }
    }
}
