required init args should default to None and raise an error

[laroque]

Due to nested inheritance, it can be really hard to debug errors that look like TypeError: __init__() takes exactly 3 arguments (2 given)....

Solution:

use something that looks like this for init methods:

def __init__(self, some_required_arg=None, **kwargs):
    if some_required_arg is None:
        raise exceptions.DriplineValueError('a valid value for "some_required_arg" is required to __init__() <this class name>')

[laroque]

this should be fixed, at least in core; hopefully this will make it easier to debug broken config files.