def setup(mail_verification=False, require_user_to_be_verified=False,
    use_sessions_when_client_calls_endpoint=False, *fixed_user_attributes):
    """Use `mail_verification` to control whether the register function should automatically try to verify the users' email. You can also manually do that by calling `serverly.user.mail.send_verification_email()`.

    If `require_user_to_be_verified`, users will only authenticate if their email is verified.

    If `use_sessions_when_client_calls_endpoint`, a new user activity will automatically be registered if the client uses an endpoint.

    `fixed_user_attributes` is a list which contains the attribute names of User attributes which may not be changed by the API. Useful for roles.
    """
    global verify_mail, only_user_verified, use_sessions, persistant_user_attributes
    verify_mail = mail_verification
    only_user_verified = require_user_to_be_verified
    use_sessions = use_sessions_when_client_calls_endpoint
    persistant_user_attributes = fixed_user_attributes
