def _find_next_digest(self, digests, bucket, last_key, last_start_date,
                          cb=None, is_cb_conditional=False, message=None):
        next_key, next_end_date = self._get_last_digest(digests, last_key)
        if cb and (not is_cb_conditional or next_key):
            cb(bucket=bucket, next_key=next_key, last_key=last_key,
               next_end_date=next_end_date, last_start_date=last_start_date,
               message=message)
        return next_key, next_end_date
Finds the next digest in the bucket and invokes any callback.
dataset/ETHPy150Open aws/aws-cli/awscli/customizations/cloudtrail/validation.py/DigestTraverser._find_next_digest