In Python

raise ValueError("custom message")

• https://stackoverflow.com/questions/2052390/manually-raising-throwing-an-exception-in-python
• https://stackoverflow.com/questions/1156023/print-current-call-stack-from-a-method-in-code

In PyCharm

Top right drop-down menu:

Edit configurations

python interpreter:

<python environment=""></python>

place breakpoint (not in the template, click the left border)

--OK--

Debug 'name' (F5) (At least with VS Code keymap)