NameError: name 'null' is not defined

Hi when I tried running py file in AWS I met the following question:

In py file, ‘null’ is located at:

Before I met this information, I also met that “NameError: name ‘true’ is not defined”, which I solved by changing ‘true’ to ‘True’. But it doesn’t work for the null error.
Could you please help me figure out this problem? Thank you!

You can’t run ipynb file on python3 they are different. Either run Jupyter notebooks on AWS or run the python3 commands from the notebook in Python3 shell.