def cached_request(self, request):
        """
        Return a cached response if it exists in the cache, otherwise
        return False.
        """
        cache_url = self.cache_url(request.url)
        logger.debug('Looking up "%s" in the cache', cache_url)
        cc = self.parse_cache_control(request.headers)

        # Bail out if the request insists on fresh data
        if 'no-cache' in cc:
            logger.debug('Request header has "no-cache", cache bypassed')
            return False

        if 'max-age' in cc and cc['max-age'] == 0:
            logger.debug('Request header has "max_age" as 0, cache bypassed')
            return False

        # Request allows serving from the cache, let's see if we find something
        cache_data = self.cache.get(cache_url)
        if cache_data is None:
            logger.debug('No cache entry available')
            return False

        # Check whether it can be deserialized
        resp = self.serializer.loads(request, cache_data)
        if not resp:
            logger.warning('Cache entry deserialization failed, entry ignored')
            return False

        # If we have a cached 301, return it immediately. We don't
        # need to test our response for other headers b/c it is
        # intrinsically "cacheable" as it is Permanent.
        # See:
        #   https://tools.ietf.org/html/rfc7231#section-6.4.2
        #
        # Client can try to refresh the value by repeating the request
        # with cache busting headers as usual (ie no-cache).
        if resp.status == 301:
            msg = ('Returning cached "301 Moved Permanently" response '
                   '(ignoring date and etag information)')
            logger.debug(msg)
            return resp

        headers = CaseInsensitiveDict(resp.headers)
        if not headers or 'date' not in headers:
            if 'etag' not in headers:
                # Without date or etag, the cached response can never be used
                # and should be deleted.
                logger.debug('Purging cached response: no date or etag')
                self.cache.delete(cache_url)
            logger.debug('Ignoring cached response: no date')
            return False

        now = time.time()
        date = calendar.timegm(
            parsedate_tz(headers['date'])
        )
        current_age = max(0, now - date)
        logger.debug('Current age based on date: %i', current_age)

        # TODO: There is an assumption that the result will be a
        #       urllib3 response object. This may not be best since we
        #       could probably avoid instantiating or constructing the
        #       response until we know we need it.
        resp_cc = self.parse_cache_control(headers)

        # determine freshness
        freshness_lifetime = 0

        # Check the max-age pragma in the cache control header
        if 'max-age' in resp_cc and resp_cc['max-age'].isdigit():
            freshness_lifetime = int(resp_cc['max-age'])
            logger.debug('Freshness lifetime from max-age: %i',
                         freshness_lifetime)

        # If there isn't a max-age, check for an expires header
        elif 'expires' in headers:
            expires = parsedate_tz(headers['expires'])
            if expires is not None:
                expire_time = calendar.timegm(expires) - date
                freshness_lifetime = max(0, expire_time)
                logger.debug("Freshness lifetime from expires: %i",
                             freshness_lifetime)

        # Determine if we are setting freshness limit in the
        # request. Note, this overrides what was in the response.
        if 'max-age' in cc:
            try:
                freshness_lifetime = int(cc['max-age'])
                logger.debug('Freshness lifetime from request max-age: %i',
                             freshness_lifetime)
            except ValueError:
                freshness_lifetime = 0

        if cc in 'min-fresh':
            try:
                min_fresh = int(cc['min-fresh'])
            except ValueError:
                min_fresh = 0
            # adjust our current age by our min fresh
            current_age += min_fresh
            logger.debug('Adjusted current age from min-fresh: %i',
                         current_age)

        # Return entry if it is fresh enough
        if freshness_lifetime > current_age:
            logger.debug('The response is "fresh", returning cached response')
            logger.debug('%i > %i', freshness_lifetime, current_age)
            return resp

        # we're not fresh. If we don't have an Etag, clear it out
        if 'etag' not in headers:
            logger.debug(
                'The cached response is "stale" with no etag, purging'
            )
            self.cache.delete(cache_url)

        # return the original handler
        return False
dataset/ETHPy150Open ionrock/cachecontrol/cachecontrol/controller.py/CacheController.cached_request/swapped operands of `in`