Setting exit code in Python when an exception is raised

$ cat e.py
raise Exception
$ python e.py
Traceback (most recent call last):
  File "e.py", line 1, in <module>
    raise Exception
Exception
$ echo $?
1

I would like to change this exit code from 1 to 3 while still dumping the full stack trace. What's the best way to do this?