Generic repository pattern implementation for NHibernate

NHibernateRepository.cs

public interface IRepository<T>
{
  IEnumerable<T> GetAll();
  T GetByID(int id);
  T GetByID(Guid key);
  void Save(T entity);
  void Delete(T entity);
}

public class Repository<T> : IRepository<T>
{
  protected readonly ISession Session;

  public Repository(ISession session)
  {
    Session = session;
  }

  public IEnumerable<T> GetAll()
  {
    return Session.Query<T>();
  }

  public T GetByID(int id)
  {
    return Session.Get<T>(id);
  }

  public T GetByID(Guid key)
  {
    return Session.Get<T>(key);
  }

  public void Save(T entity)
  {
    Session.Save(entity);
    Session.Flush();
  }

  public void Delete(T entity)
  {
    Session.Delete(entity);
    Session.Flush();
  }
}