'Return the timedelta an entry that has failed `fail_count` times before should wait before being retried.'

def retry_time(self, fail_count, config):

    base_retry_time = parse_timedelta(config[u'retry_time'])
    base_retry_secs = ((base_retry_time.days * 86400) + base_retry_time.seconds)
    retry_secs = (base_retry_secs * (config[u'retry_time_multiplier'] ** fail_count))
    max = (((60 * 60) * 24) * 30)
    if (retry_secs > max):
        retry_secs = max
    return timedelta(seconds=retry_secs)
