A simple demo of the ordering of try/except/else/finally in python

stdout

testing dont_raise
try
else
finally

testing raise_known
try
except KnownException
finally

testing raise_unknown
try
Traceback (most recent call last):
  File "try_except_else_finally_demo.py", line 17, in test_func
    func()
  File "try_except_else_finally_demo.py", line 40, in raise_unknown
    raise UnknownException()
UnknownException

finally

try_except_else_finally_demo.py

import sys
import traceback


class KnownException(Exception):
    """This is the exception we expected"""


class UnknownException(Exception):
    """This is NOT the exception we expected"""


def test_func(func):
    print(f"testing {func.__name__}")
    try:
        print("try")
        func()
    except KnownException as err:
        print(f"except {err.__class__.__name__}")
    except ValueError:
        print("except ValueError")
    except Exception as err:
        print("".join(traceback.format_exception(err, err, err.__traceback__)))
    else:
        print("else")
    finally:
        print("finally")
        print()


def dont_raise():
    pass


def raise_known():
    raise KnownException()


def raise_unknown():
    raise UnknownException()


def main():
    test_func(dont_raise)
    test_func(raise_known)
    test_func(raise_unknown)


if __name__ == "__main__":
    main()