这是开放/封闭原则吗？如果不是

public interface IEntity {
int Id { get; set; }
}

public class User : IEntity {
    public int Id { get; set; }
}

public abstract class RepositoryBase<TEntity> where TEntity : IEntity {

    public bool Save(TEntity entity) {
        if (!IsValid(entity)) return false;

        // Write to data store

        return true;
    }

    public abstract TEntity CreateNew();

    protected abstract bool IsValid(TEntity entity);
}


public class UserRepository : RepositoryBase<User> {

    public override User CreateNew() {
        return new User {
            Id = 3
        };
    }

    protected override IsValid(User entity) {
        return entity.Id > 0;
    }
}