06_multicat - append error

Hi everyone.

I was doing 06_multicat notebook and run into strange error (in the Regression part on the notebook):
AttributeError: 'NoneType' object has no attribute 'append' ,
after I try to learn.lr_find().

learn.fine_tune(3, 1e-2) also doesn’t work and throws the same error.

I have done previous notebooks and it was all fine. I didn’t change the code you have provided in this part. The forums don’t seem to have the answer for this.

I’m no expert, but it looks like there is a problem with cbs, whatever it is, and I found that it is a parameter in cnn_learner and it defaults to None. So, not sure how to go about it.

Any help is much appreciated.

Many apologies! We have a fix now and will release it very soon today.

1 Like

Hi, I still have the same problem with fastai 2.2.5. The error is thrown when executing learn.lr_find() or learn.fine_tune(3, 1e-2)

AttributeError                            Traceback (most recent call last)
<ipython-input-259-d81c6bd29d71> in <module>
----> 1 learn.lr_find()


/opt/conda/lib/python3.7/site-packages/fastai/learner.py in add_cb(self, cb)
    107         return self
--> 109     def remove_cbs(self, cbs):
    110         L(cbs).map(self.remove_cb)
    111         return self

AttributeError: 'NoneType' object has no attribute 'append'

It’s quite strange that the end of the stack trace shows no call to append, but my Python knowledge is limited.

Any help is appreciated.

Sorry, false alarm. The problem disappeared after I restarted the VM.