public static ILibraryRepository <Book> GetInMemoryLibraryRepository(string dbName)
{
var options = new DbContextOptionsBuilder <LibraryContext>()
.UseInMemoryDatabase(databaseName: dbName)
.Options;
LibraryContext libraryContext = new LibraryContext(options);
libraryContext.FillDatabase();
return(new LibraryRepository(libraryContext));
}