Post-motem debugging in Python

https://realpython.com/lessons/getting-started-pdb/

$ python3 -m pdb myProgram.py

How to debug or test python scripts using inspect module and print and input?

https://stackoverflow.com/questions/3056048/filename-and-line-number-of-python-script

At the top of your script, 

from inspect import currentframe, getframeinfo

At the spot where you want to print the value of a variable,

print(f'Line #{getframeinfo(currentframe()).lineno}:\nDescription:\n{varName}\nEnd of Description\n')

input()