How to use the jupyterhub.orm.User.find function in jupyterhub

whitelist = [
            self.authenticator.normalize_username(name)
            for name in self.authenticator.whitelist
        ]
        self.authenticator.whitelist = set(whitelist)  # force normalization
        for username in whitelist:
            if not self.authenticator.validate_username(username):
                raise ValueError("username %r is not valid" % username)

        if not whitelist:
            self.log.info("Not using whitelist. Any authenticated user will be allowed.")

        # add whitelisted users to the db
        for name in whitelist:
            user = orm.User.find(db, name)
            if user is None:
                user = orm.User(name=name)
                new_users.append(user)
                db.add(user)

        db.commit()

        # Notify authenticator of all users.
        # This ensures Auth whitelist is up-to-date with the database.
        # This lets whitelist be used to set up initial list,
        # but changes to the whitelist can occur in the database,
        # and persist across sessions.
        for user in db.query(orm.User):
            try:
                yield gen.maybe_future(self.authenticator.add_user(user))
            except Exception:

self.authenticator.normalize_username(name)
            for name in self.authenticator.whitelist
        ]
        self.authenticator.whitelist = set(whitelist)  # force normalization
        for username in whitelist:
            if not self.authenticator.validate_username(username):
                raise ValueError("username %r is not valid" % username)

        if not whitelist:
            self.log.info(
                "Not using whitelist. Any authenticated user will be allowed."
            )

        # add whitelisted users to the db
        for name in whitelist:
            user = orm.User.find(db, name)
            if user is None:
                user = orm.User(name=name)
                new_users.append(user)
                db.add(user)

        db.commit()

        # Notify authenticator of all users.
        # This ensures Auth whitelist is up-to-date with the database.
        # This lets whitelist be used to set up initial list,
        # but changes to the whitelist can occur in the database,
        # and persist across sessions.
        for user in db.query(orm.User):
            try:
                await maybe_future(self.authenticator.add_user(user))
            except Exception:

def init_groups(self):
        """Load predefined groups into the database"""
        db = self.db
        for name, usernames in self.load_groups.items():
            group = orm.Group.find(db, name)
            if group is None:
                group = orm.Group(name=name)
                db.add(group)
            for username in usernames:
                username = self.authenticator.normalize_username(username)
                if not (yield gen.maybe_future(self.authenticator.check_whitelist(username))):
                    raise ValueError("Username %r is not in whitelist" % username)
                user = orm.User.find(db, name=username)
                if user is None:
                    if not self.authenticator.validate_username(username):
                        raise ValueError("Group username %r is not valid" % username)
                    user = orm.User(name=username)
                    db.add(user)
                group.users.append(user)
        db.commit()

def start(self):
        hub = JupyterHub(parent=self)
        hub.load_config_file(hub.config_file)
        hub.init_db()
        hub.hub = hub.db.query(orm.Hub).first()
        hub.init_users()
        user = orm.User.find(hub.db, self.name)
        if user is None:
            print("No such user: %s" % self.name, file=sys.stderr)
            self.exit(1)
        token = user.new_api_token()
        print(token)

for name in self.authenticator.admin_users
        ]
        self.authenticator.admin_users = set(admin_users)  # force normalization
        for username in admin_users:
            if not self.authenticator.validate_username(username):
                raise ValueError("username %r is not valid" % username)

        if not admin_users:
            self.log.warning("No admin users, admin interface will be unavailable.")
            self.log.warning("Add any administrative users to `c.Authenticator.admin_users` in config.")

        new_users = []

        for name in admin_users:
            # ensure anyone specified as admin in config is admin in db
            user = orm.User.find(db, name)
            if user is None:
                user = orm.User(name=name, admin=True)
                new_users.append(user)
                db.add(user)
            else:
                user.admin = True

        # the admin_users config variable will never be used after this point.
        # only the database values will be referenced.

        whitelist = [
            self.authenticator.normalize_username(name)
            for name in self.authenticator.whitelist
        ]
        self.authenticator.whitelist = set(whitelist)  # force normalization
        for username in whitelist:

def find_user(self, name):
        """Get a user by name

        return None if no such user
        """
        orm_user = orm.User.find(db=self.db, name=name)
        return self._user_from_orm(orm_user)

}
        user = self.authenticator.get_or_create_user(**user_info)

        alert, message = self.get_result_message(user)

        otp_secret, user_2fa = '', ''
        if user:
            otp_secret = user.otp_secret
            user_2fa = user.has_2fa

        user = self.authenticator.get_or_create_user(**user_info)

        username = user_info['username']
        pw = user_info['pw']
        if self.authenticator.authenticate(self, username, pw):
            user = User.find(self.db, username)
            self.redirect(self.get_next_url(user=user), permanent=False)
        else:
            html = self.render_template(
                'signup.html',
                ask_email=self.authenticator.ask_email_on_signup,
                result_message=message,
                alert=alert,
                two_factor_auth=self.authenticator.allow_2fa,
                two_factor_auth_user=user_2fa,
                two_factor_auth_value=otp_secret,
            )
            self.finish(html)