def complete_profile(f, credentials, session_token_written, mfa_serial_written):
    """
    Append session token and mfa serial if needed

    :param f:
    :param credentials:
    :param session_token_written:
    :param mfa_serial_written:
    :return:
    """
    session_token = credentials['SessionToken'] if 'SessionToken' in credentials else None
    mfa_serial = credentials['SerialNumber'] if 'SerialNumber' in credentials else None
    if session_token and not session_token_written:
        f.write('aws_session_token = %s\n' % session_token)
    if mfa_serial and not mfa_serial_written:
        f.write('aws_mfa_serial = %s\n' % mfa_serial)