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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def stream(self, iso_code=values.unset, continent=values.unset, country_code=values.unset, low_risk_numbers_enabled=values.unset, high_risk_special_numbers_enabled=values.unset, high_risk_tollfraud_numbers_enabled=values.unset, limit=None, page_size=None):
 """ Streams CountryInstance records from the API as a generator stream. This operation lazily loads records as efficiently as possible until the limit is reached. The results are returned as a generator, so this operation is memory efficient. :param unicode iso_code: Filter to retrieve the country permissions by specifying the ISO country code :param unicode continent: Filter to retrieve the country permissions by specifying the continent :param unicode country_code: Country code filter :param bool low_risk_numbers_enabled: Filter to retrieve the country permissions with dialing to low-risk numbers enabled :param bool high_risk_special_numbers_enabled: Filter to retrieve the country permissions with dialing to high-risk special service numbers enabled :param bool high_risk_tollfraud_numbers_enabled: Filter to retrieve the country permissions with dialing to high-risk toll fraud numbers enabled :param int limit: Upper limit for the number of records to return. stream() guarantees to never return more than limit. Default is no limit :param int page_size: Number of records to fetch per request, when not set will use the default value of 50 records. If no page_size is defined but a limit is defined, stream() will attempt to read the limit with the most efficient page size, i.e. min(limit, 1000) :returns: Generator that will yield up to limit results :rtype: list[twilio.rest.voice.v1.dialing_permissions.country.CountryInstance] """

        limits = self._version.read_limits(limit, page_size)

        page = self.page(
            iso_code=iso_code,
            continent=continent,
            country_code=country_code,
            low_risk_numbers_enabled=low_risk_numbers_enabled,
            high_risk_special_numbers_enabled=high_risk_special_numbers_enabled,
            high_risk_tollfraud_numbers_enabled=high_risk_tollfraud_numbers_enabled,
            page_size=limits['page_size'],
        )

        return self._version.stream(page, limits['limit'], limits['page_limit'])