public void InsertTest() { LedgerBook book = getSampleBook(); Console.WriteLine("The Items Before Insert:"); foreach (LedgerItem item in book) { Console.WriteLine(item); } Console.WriteLine("Inserting new item at index 0"); book.Insert(0 , LedgerItem.Create(new DateTime(2020, 1, 19), "New Installation of Boiler", LedgerItemCreateMode.Debit, 1024.22)); foreach (LedgerItem item in book) { Console.WriteLine(item); } Console.WriteLine("Inserting new item at index 3"); book.Insert(3 , LedgerItem.Create(new DateTime(2019, 12, 2), "New Installation of Boiler", LedgerItemCreateMode.Debit, 884.8)); foreach (LedgerItem item in book) { Console.WriteLine(item); } Console.WriteLine("Inserting new item at index Count"); book.Insert(book.Count , LedgerItem.Create(new DateTime(2077, 5, 6), "New Installation of Boiler", LedgerItemCreateMode.Debit, 2884.8)); foreach (LedgerItem item in book) { Console.WriteLine(item); } }