'Adds a course mode to the test course.'

def _add_course_mode(self, min_price=50, mode_slug='honor', expiration_date=None):

    mode = CourseModeFactory.create()
    mode.course_id = self.course.id
    mode.min_price = min_price
    mode.mode_slug = mode_slug
    mode.expiration_date = expiration_date
    mode.save()
    return mode
