def retrieve(self, request):
        """Look up request in cache, skipping if verb is forbidden.

        :param requests.Request request: HTTP request

        """
        if CACHE_VERBS not in request.method:
            return
        try:
            response = self.data[request.url]['response']
            logger.info('Retrieved response from cache')
            return response
        except KeyError:
            return None
dataset/ETHPy150Open jmcarp/robobrowser/robobrowser/cache.py/RoboCache.retrieve/swapped operands of `not in`