def create_user(first_name, last_name, email, phone_number, dob, address_id):
    """
    Creates immutable user data structure

    :param first_name: user's first name (string)
    :param last_name: user's last name (string)
    :param email: user's email (string)
    :param phone_number: user's phone number (string)
    :param dob: user's date of birth (string)
    :return: (tuple)
    """

    return (first_name, last_name, email, phone_number, dob, address_id)