Trace recursively, but only my code

Hi,

I would like to trace the http request handling of Django in my development environment.

But I am sure that the bug is in my code, not in the code of Django.

I would like to see every line of my code, excluding Django, standard library and other libraries.

I had a look at the arguments which `snoop()` accepts, but I think it is not possible up to now.

Would you accept a PR which implements this?

Do you have a hint how to implement this?