'Returns the minimum price of the course int he appropriate currency over all the
course\'s *verified*, non-expired modes.
Assuming all verified courses have a minimum price of >0, this value should always
be >0.
If no verified mode is found, 0 is returned.'

@classmethod
def min_course_price_for_verified_for_currency(cls, course_id, currency):

    modes = cls.modes_for_course(course_id)
    for mode in modes:
        if ((mode.currency.lower() == currency.lower()) and (mode.slug == 'verified')):
            return mode.min_price
    return 0
