def evaluate_challenge()

in cassandra_sigv4/auth.py [0:0]


    def evaluate_challenge(self, challenge):
        challenge = _ensure_b(challenge)
        nonce = _extract_nonce(challenge)
        request_timestamp = datetime.utcnow()
        credentials = self.session.get_credentials()
        signature = _generate_signature(nonce, request_timestamp, credentials,
                                        self.session.region_name)
        response = "signature={0},access_key={1},amzdate={2}".format(signature,
                                                                     credentials.access_key,
                                                                     _format_timestamp(
                                                                         request_timestamp))

        if credentials.token:
            response += ",session_token={0}".format(credentials.token)
        return response