PermissionError: [Errno 13] Permission denied Windows

I am doing a web application with flask and in one part an image is uploaded but when I do the process I get the error that I do not have permissions, I already executed as administrator the windows CMD, I gave it permissions of the folder in the properties and it's still coming out. Does anyone know the solution ?, I show the code I'm doing:

console:

PermissionError: [Errno 13] Permission denied: 'C:\Users\useradmin\Documents\python\proyecto\web/static/assets'

uploadfiles.py

import os
import smtplib
from flask import json, session, request
from werkzeug.utils import secure_filename

ROOT_ABSOLUTE_PATH = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
UPLOAD_FOLDER = ROOT_ABSOLUTE_PATH+"/static/assets"

ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'])

class FilesPrueba():

  def __init__(self, request_file):
    self.request_file = request_file

  def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

  def uploas_images(self)
    file = self.request_file.files['files[]']
    if file and FilesPrueba.allowed_file(file.filename):
       filename = secure_filename(file.filename)
       print('filename: ', filename)
       file.save(os.path.join(UPLOAD_FOLDER), filename)
    #.....

thank you very much.