UnboundLocalError local variable torch referenced before assignment

一开始 import torch，在 vscode 中，torch 显示灰色

这是因为在代码的某个地方又使用了 import torch, 去掉就OK了

在 stackoverflow 里看到的解释：----链接----- ，580多赞的那个回答

The Python interpreter sees this at module load time and decides (correctly so) that the global scope's Var1 should not be used inside the local scope, which leads to a problem when you try to reference the variable before it is locally assigned.