ConsecutiveGroupBy using Generics

ConsecutiveGroupBy.cs

//A consecutive groupby in Linq and C#
//proof of concept for merging some date range like objects

//Based on https://www.daniweb.com/programming/software-development/code/488977/linq-consecutive-groupby

using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsecutiveGroupBy {
    public static class Extensions {
        public static IQueryable<T> ConsecutiveGroupBy<T, TProp>(
            this IQueryable<T> instance,
            Func<T, TProp> orderBy,
            Func<T, T, bool> isAdjacentFunc,
            Action<T, T> mergeFunc)
            {
            List<T> result = new List<T>();
            if (instance != null) {
                result =
                    instance
                    .OrderBy(orderBy)
                    .Aggregate(
                        new List<T>(), (list, item) => {
                            if (list.Count == 0 || !isAdjacentFunc(list.Last(), item)) {
                                list.Add(item);
                            } 
                            else {
                                mergeFunc(list.Last(),item);
                            }
                            return list;
                        });
            }
            return result.AsQueryable();
        }
    }
    public class TestClass {
        public int From { get; set; }
        public int To { get; set; }
    }
    class Program {
        static void Main() {
            var data = new List<TestClass>
            {
                    new TestClass { From = 26, To = 30 },
                    new TestClass { From = 21, To = 25 },
                    new TestClass { From = 15, To = 20 },
                    new TestClass { From = 8, To = 9 },
                    new TestClass { From = 8, To = 11 },
                    new TestClass { From = 4, To = 7 },
                    new TestClass { From = 1, To = 2 }
                }.AsQueryable();

            var consecutiveKeys = data.ConsecutiveGroupBy(item => item.From,
                                                         (current, next) => current.To + 1 >= next.From,
                                                         (a, b) => { if (a.To < b.To) { a.To = b.To; } }
                                                         );

            foreach (var k in consecutiveKeys) {
                Console.WriteLine("{0} - {1}", k.From,k.To);
                }
            }


    }
}