def fit_scale(self, scale):
        if scale >= 1:
            return 1.0
        elif scale <= 0:
            return 0.0
        else:
            return scale
@return: a scale >= 0 and <= 1
dataset/ETHPy150Open istresearch/scrapy-cluster/crawler/crawling/distributed_scheduler.py/DistributedScheduler.fit_scale