Question about "gradient"

[myc1998]

When doing fasterrcnn-gradcam, after debugging, I found that the gradient parameter has always been None. The gradient parameter never gets data. Then it will be reported: 'NoneType' object is not subscriptable. There is no problem with the image path after checking. It would be appreciated if you could help.

[Zhaowss]

我也出现了这个问题这个怎么解决呀