A simple program consisting of a start-able setting file and a worker that contains all the code. The worker can access settings without blowing up if a setting doesn't exist.

startme.py

#!/usr/bin/env python

# The exercise is to make a start-able config file
#
# This file contains some settings and minimal code to make it run.

name = "Anonymous"
weight = 80
size = 1.80


if __name__ == "__main__":
    from worker import run
    run()

worker.py

#!/usr/bin/env python

import startme


class UnitError(Exception):
    pass


class Wrapper(object):

    def __init__(self, wrapped):
        self.wrapped = wrapped

    def __getattr__(self, name):
        return getattr(self. wrapped, name, None)


SETTINGS = Wrapper(startme)


def calc_bmi(weight, size):
    """ returns the body-mass-index

        Args
            weight: body mass in Kilogram
            size: body length in meter

        Examples
            >>> calc_bmi(85, 1.85)
            24.84
            >>> calc_bmi(100, 180)
            Traceback (most recent call last):
                ...
            UnitError: Please insert size in meter.
    """
    if not (weight and size):
        raise UnitError("Size and / or weight are not set.")
    if size > 10:
        raise UnitError("Please insert size in meter.")
    return round(float(weight) / size**2, 2)


def run():
    """ prints optional name and BMI

        Examples (this is expected to fail if startme.py is changed)
            >>> run()
            BMI Anonymous: 24.69
    """
    name = " " + SETTINGS.name if SETTINGS.name else ""
    print "BMI%s: %s" % (name, calc_bmi(SETTINGS.weight, SETTINGS.size))


if __name__ == "__main__":
    import doctest
    doctest.testmod()

Nett, habe es übernommen. Danke!