How to use data obtained from DB as values in add_argument() when the flask app starts?

I have the following project structure for a flask app using flask-restx

.
├── app
│   ├── extensions.py
│   ├── __init__.py
│   └── pv_dimensioning
│       ├── controller.py
│       ├── __init__.py
│       ├── models
│       │   ├── dto.py
│       │   ├── __init__.py
│       │   └── vendor_models.py
│       ├── services
│       │   ├── calculator.py
│       │   ├── database.py
│       │   ├── data.py
│       │   ├── db_crud.py
│       │   ├── __init__.py
│       │   └── processor.py
│       └── utils
│           ├── decode_verify_jwt.py
│           ├── decorator.py
│           └── __init__.py
├── config.py
├── main.py
├── package.json
├── package-lock.json
├── Pipfile
├── Pipfile.lock
├── README.md
├── serverless.yml
└── tests
    ├── __init__.py
    ├── test_calculator.py
    ├── test_config.py
    └── test_processor.py

In controller.py, I am adding the add_argument() statements and parsing them in the api routes. In one of the add_argument() statement, I would like to add choices for the user. For getting the choices, I am querying from the database and getting a list of values available. I then convert this list to a tuple, assign it to a variable, and pass it as choices parameter in the add_argument()

My codes:

data.py

from ..models.vendor_models import AdminVendor

def data(app):
    values = AdminVendor.query.all()
    v = [value.name for value in values]
    return {'v': tuple(v)}

controller.py

from flask_restx import Resource, reqparse

parser = reqparse.RequestParser()

parser.add_argument(
    "vendor",
    choices=vendors, # <--- The values of v should be added here
    help="Select the vendor"
)

@ns.route("/")
class UserOutput(Resource):
    @ns.doc(
        "Get calculated response",
        responses={
            200: "Values returned",
            400: "Validation Error",
            403: "Not authorized"
        },
    )
    @ns.expect(parser, validation=True)
    def get(self):
        args = parser.parse_args()
        return DimensionCalculator.inputs(**args), 200

where ns is the namespace.

My __init__.py file in the app folder is as follows:

from flask import Flask

from .extensions import cors, db, ma

def create_app(app_config):
    app = Flask(__name__)

    app.config.from_object(app_config)

    register_blueprints(app)
    register_extensions(app)
    return app

def register_extensions(app):
    cors.init_app(app)
    db.init_app(app)
    ma.init_app(app)

def register_blueprints(app):
    from .pv_dimensioning import dimensioning_blueprint
    app.register_blueprint(dimensioning_blueprint)

and the entry point to the app is main.py

import os

from app import create_app
from app.extensions import db
from app.pv_dimensioning.services.data import data
from config import config_by_name

config_name = os.getenv("FLASK_CONFIG") or "default"
app_config = config_by_name[config_name]
app = create_app(app_config)

db.create_all(app=app)

with app.app_context():
    v = data(app)

print(v)

The output of print(v) is as follows:

{'v': ('Solarmodul Canadian Solar HiKu CS3L-370MS 370Wp', 'Solarmodul Longi LR4-60HIH-370M, 370Wp', 'Solarmodul Solar Fabrik mono S3 - Halfcut 360Wp', 'Solarmodul Energetica e.Classic M HC black - 360Wp', 'Solarmodul Yingli YL280P-29b-YGE 60 Cell Series 2 - poly, 280Wp', 'Solarmodul Suntech Power STP370S-B60/Wnh, 370Wp', 'Solarmodul AXITEC AXIworldpremium X HC AC-340MH/120S, 340Wp', 'Solarmodul Longi LR4-72HIH-440M, 440Wp', 'Solarmodul Seraphim SRP-330-BMB-DG 330Wp', 'Solarmodul Sharp NU-JD 440Wp')}

I want these values of v to be used in controller.py in the 'vendor' argument.

I have tried getting the values of v from main.py by adding from main import v in the controller.py, but it shows the following error

ImportError: cannot import name 'v' from 'main'

What is the mistake that I am doing?

Any help is appreciated.

Thanks

from How to use data obtained from DB as values in add_argument() when the flask app starts?