Cannot save adversarial examples when using MultiAttack

[tsunghan-wu]

Hi,

I encountered errors when using MultiAttack.
Here is my code segment:

# cifar100_eval_loader = ... (initialize my dataloader)
eps = 8 / 255
alpha = 2 / 255
atk1 = TIFGSM(srcnet, eps=eps, alpha=alpha, steps=40)
atk2 = DIFGSM(srcnet, eps=eps, alpha=alpha, steps=40)
atk = MultiAttack([atk1, atk2])
atk.set_return_type('int')  # Save as integer.
atk.save(data_loader=cifar100_eval_loader, save_path=save_path, verbose=True)

However, the following error messages occurs:

- Save complete!
Traceback (most recent call last):
  File "/tmp2/attack/src/adv_attack.py", line 162, in <module>
    atk.save(data_loader=cifar100_eval_loader, save_path=save_path, verbose=True)
  File "/home/tsunghan/miniconda3/envs/SPML/lib/python3.9/site-packages/torchattacks/attacks/multiattack.py", line 105, in save
    rob_acc, l2, elapsed_time = super().save(data_loader, save_path, verbose, return_verbose)
TypeError: cannot unpack non-iterable NoneType object

I wonder that whether the MultiAttack.save() method contains bugs?
Thanks!

[Harry24k]

return_verbose=False raises the problem in version 3.2.0.
Bug fixed in version 3.2.2.
Thanks!