How to use the tokendito.helpers.prepare_payload function in tokendito

def duo_mfa_verify(duo_info, txid):
    """Verify MFA challenge completion.

    After the user has received the MFA challenge, query the Duo API
    until the challenge is completed.

    :param duo_info: dict of parameters for Duo.
    :param mfa_option: the user's selected second factor.
    :return txid: Duo transaction ID used to track this auth attempt.
    """
    url = "https://{}/frame/status".format(duo_info["host"])
    challenged_mfa = helpers.prepare_payload(txid=txid, sid=duo_info["sid"])
    challenge_result = None

    while True:
        logging.debug("Waiting for MFA challenge response")
        mfa_result = duo_api_post(url, payload=challenged_mfa)
        verify_mfa = get_mfa_response(mfa_result)
        challenge_result, challenge_reason = parse_challenge(
            verify_mfa, challenge_result)

        if challenge_result is None:
            continue
        elif challenge_result == "success":
            logging.debug("Successful MFA challenge received")
            break
        elif challenge_result == "failure":
            logging.critical("MFA challenge has failed:"

factor_options = get_duo_devices(duo_auth_response)
    mfa_index = helpers.select_preferred_mfa_index(
        factor_options, factor_key="factor", subfactor_key="device")

    mfa_option = factor_options[mfa_index]
    logging.debug("Selected MFA is [{}]".format(mfa_option))
    passcode = set_passcode(mfa_option)

    txid = duo_mfa_challenge(duo_info, mfa_option, passcode)
    verify_mfa = duo_mfa_verify(duo_info, txid)

    # Make factor callback to Duo
    sig_response = duo_factor_callback(duo_info, verify_mfa)

    # Prepare for Okta callback
    payload = helpers.prepare_payload(id=duo_info["factor_id"],
                                      sig_response=sig_response,
                                      stateToken=duo_info["state_token"])
    headers = {}
    headers["content-type"] = "application/json"
    headers["accept"] = "application/json"

    return payload, headers, duo_info["okta_callback_url"]

"""
    logging.debug("Handle user MFA options")

    logging.debug("User MFA options selected: [{}]".format(
        selected_mfa_option['factorType']))
    if selected_mfa_option['factorType'] == 'push':
        return push_approval(headers, mfa_challenge_url, payload)

    if settings.mfa_response is None:
        logging.debug("Getting verification code from user.")
        print('Type verification code and press Enter')
        settings.mfa_response = helpers.get_input()

    # time to verify the mfa method
    payload = helpers.prepare_payload(
        stateToken=primary_auth['stateToken'], passCode=settings.mfa_response)
    mfa_verify = okta_verify_api_method(mfa_challenge_url, payload, headers)
    logging.debug("mfa_verify [{}]".format(json.dumps(mfa_verify)))

    return mfa_verify