protected void FriendAssert(IFriendKey key)
{
if (key == null || key.Id == null || key.Id.GetType() != typeof(TFriend))
{
throw new Exception("No right to execute the called method.");
}
}
public void f(IFriendKey key)
{
FriendAssert(key);
Console.WriteLine("ONLY class B can execute this method successfully, even though it is declared public.");
}
