def next_requests(self):
        """Returns a request to be scheduled or none."""
        # XXX: Do we need to use a timeout here?
        found = 0
        datas = self.fetch_data(self.redis_key, self.redis_batch_size)
        for data in datas:
            reqs = self.make_request_from_data(data)
            if isinstance(reqs, Iterable):
                for req in reqs:
                    yield req
                    # XXX: should be here?
                    found += 1
                    self.logger.info(f"start req url:{req.url}")
            elif reqs:
                yield reqs
                found += 1
            else:
                self.logger.debug(f"Request not made from data: {data}")

        if found:
            self.logger.debug(f"Read {found} requests from '{self.redis_key}'")
Returns a request to be scheduled or none.
src/scrapy_redis/spiders.py