9. public interface IRepository<T> where T : class { IEnumerable<T> GetAll(); //一覧 T Find(int id); //取得 T Create(T entity); //作成 void Update(T entity); //更新 void Delete(T entity); //削除 } public interface IUserRepository : IRepository<User> { } 10. public class UserRepository : IUserRepository { private readonly DbContext db; public UserRepository(DbContext db) => this.db = db; public IEnumerable<U