How to use the py4web.URL function in py4web

def test_url(self):
        request.app_name = "_default"
        self.assertEqual(URL("index"), "/index")
        request.app_name = "app"
        self.assertEqual(URL("index"), "/app/index")
        self.assertEqual(URL("a", "b", vars=dict(x=1), hash="y"), "/app/a/b?x=1#y")

def test_url(self):
        request.app_name = "_default"
        self.assertEqual(URL("index"), "/index")
        request.app_name = "app"
        self.assertEqual(URL("index"), "/app/index")
        self.assertEqual(URL("a", "b", vars=dict(x=1), hash="y"), "/app/a/b?x=1#y")

def register(self, fields, send=True):
        if self.use_username:
            fields["username"] = fields.get("username", "").lower()
        fields["email"] = fields.get("email", "").lower()
        token = str(uuid.uuid4())
        fields["action_token"] = "pending-registration:%s" % token
        res = self.db.auth_user.validate_and_insert(**fields)
        if send and res.get("id"):
            self._link = link = URL(
                self.route, "verify_email", vars=dict(token=token), scheme=True
            )
            self.send("verify_email", fields, link=link)
        return res

db = self.db
        value = email.lower()
        if self.use_username:
            query = (
                (db.auth_user.email == value)
                if "@" in value
                else (db.auth_user.username == value)
            )
        else:
            query = db.auth_user.email == value
        user = db(query).select().first()
        if user and not user.action_token == "account-blocked":
            token = str(uuid.uuid4())
            user.update_record(action_token="reset-password-request:" + token)
            if send:
                self._link = link = URL(
                    self.route,
                    "api",
                    "reset_password",
                    vars=dict(token=token),
                    scheme=True,
                )
                self.send("reset_password", user, link=link)
            return token

def grid(self, table):
        name = "vue%s" % str(uuid.uuid4())[:8]
        return DIV(
            self.mtable(table),
            TAG.SCRIPT(_src=URL("static/js/axios.min.js")),
            TAG.SCRIPT(_src=URL("static/js/vue.min.js")),
            TAG.SCRIPT(_src=URL("static/js/utils.js")),
            TAG.SCRIPT(_src=URL("static/components/mtable.js")),
            TAG.SCRIPT(XML('var app=utils.app("%s"); app.start()' % name)),
            _id=name,
        )