Autthor Search

//8.Author Search
public static string GetAuthorNamesEndingIn(BookShopContext context, string input)
        {
             var books = context.Books.Where(b => b.Author.FirstName.EndsWith(input))
                                     .Select(b => new
                                     {
                                         AuthorFirstName = b.Author.FirstName,
                                         AthorLastName = b.Author.LastName,

                                     })
                                     .OrderBy(b=>b.AuthorFirstName)
                                     .ThenBy(b=>b.AthorLastName)
                                     .ToHashSet();

            return string.Join(Environment.NewLine, books.Select(b=>$"{b.AuthorFirstName} {b.AthorLastName}"));
        }