Sparrow fortune telling scam

A man wanted to test him, so he held a sparrow in his hand and said to the blind man, Sir, I have a life in my hand. Are you alive or dead? This man thinks that the blind can't see. If he says alive, I'll strangle him. If he says dead, I'll let him go. Blind people lose anyway. I didn't expect the blind man to say that it was very simple. You keep him alive, you crush him. I'm good at fortune telling, do you agree?