a.py

def retry(func, timeout=DEFAULT_TIMEOUT, retry_delay=DEFAULT_SLEEP, backoff=DEFAULT_BACKCOFF,
          retry_exceptions=(RateLimit, socket.error, socket.gaierror, httplib.NotConnected,
                            httplib.ImproperConnectionState), *args, **kwargs):
    """
    Retry decorator helps to handle common exception.
    :param timeout: Default timeout
    """
    timeout = timeout
    bsleep = retry_delay
    backoff = backoff
    end = datetime.now() + timedelta(seconds=timeout)
    exc_info = None
    while datetime.now() < end:
        try:
            result = func(*args, **kwargs)
            return result
        except Exception, exc:
            if any((isinstance(exc, exc_type) for exc_type in retry_exceptions)):
                if isinstance(RateLimit, exc):
                    time.sleep(exc.retry_after)
                    end = datetime.now() + timedelta(seconds=exc.retry_after + timeout)
                else:
                    exc_info = sys.exc_info()
                    time.sleep(bsleep)
                    bsleep += backoff
    if exc_info:
        raise exc_info[1]