While developing, you might face an unexpected behavior of your code or a crash, and you will want to dive into it, see the state of the variables, and check what's going on to understand how to handle the unexpected situation so that the software behaves properly.
This is typically part of debugging and usually requires dedicated tools, debuggers, to make your life easier (ever found yourself throwing print statements everywhere around the code just to see value of some variable?).
The Python standard library comes with a very powerful debugger, and while other third-party solutions exist, the internal pdb debugger is very powerful and is able to help you in nearly all situations.