def cache_rate(self, currency, date, rate):
if not self.is_supported(defaults.INTERNAL_CURRENCY):<EOL><INDENT>logger.info('<STR_LIT>'.format(currency))<EOL><DEDENT>else:<EOL><INDENT>cache.set(_cache_key(currency, date), str(rate), _cache_timeout(date))<EOL><DEDENT>
Cache a rate for future use