def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def wait_time_gen():
        count = 0
        while True:
            rand = random.randrange(round(interval.total_seconds()))
            tmp = round(start + interval.total_seconds() * count + rand - loop.time())
            yield tmp
            count += 1