Learn.lr_find() returns AttributeError: 'NoneType' object has no attribute 'update'

Hello, I am a quite new comer in fastai; when using learn.lr_find(); it reports:
File “/home/zenglinlin/.local/lib/python3.8/site-packages/fastprogress/fastprogress.py”, line 168, in show self.out.update(HTML(self.html_code))
AttributeError: ‘NoneType’ object has no attribute 'update’
This is the code:

This is attribute error:

Depency package:
fastbook== 0.0.18
I have checked, src.show_batch() can be run success and return images; and the version of fastai is the newest one as well.

IPython==7.3.10 is the newest version;
I also checked whether it is due to bar display problems

now I am not sure where problem rooted in;
Is it due to I am using .py instead of jupyter? I have tried jupyter with the same code; it reports like " Cuda out of memory due to cannot do multiprocess" l