How to make user-define exception behave like base class Exception?

Question

Python

Subject. There is a custom class inherited from Exception(BasedException). Prompt:
1. How to force this class to intercept all errors from try-except constructions? (How does Except do it)
2. How is exception logic built in python? How is the case of an error occurring in the class itself described? without the participation of the raise command?
The task is to create an error collector (implemented as a custom exception) with additional functionality in the form of recording errors that occur in the database.
Thank you very much in advance.