Given a target object and option key, get that option from
    the target object, either through a get_{key} method or
    from an attribute directly.

def _get_option(target_obj, key):
    """
    Given a target object and option key, get that option from
    the target object, either through a get_{key} method or
    from an attribute directly.
    """
    getter_name = 'get_{key}'.format(**locals())
    by_attribute = functools.partial(getattr, target_obj, key)
    getter = getattr(target_obj, getter_name, by_attribute)
    return getter()