Authenticate gspread with already existing session

Question

I'm stuck trying to use gspread on my flask application..

I have this authentication steps

from flask import Flask, url_for, redirect, session, request
from sql_functions import fetch_all, commit, commit_return_last_id, mysql_to_dataframe
from search_routes import search
from author_routes import author
from department_routes import department
from login_routes import authentication
from flask_sslify import SSLify
from settings import SECRET_KEY, GOOGLE_CLIENT_ID, GOOGLE_CLIENT_SECRET, GOOGLE_TOKEN_URI,GOOGLE_AUTH_URI 
from authlib.integrations.flask_client import OAuth
import gspread
from oauth2client.client import AccessTokenCredentials


app = Flask(__name__)
app.secret_key = SECRET_KEY
sslify = SSLify(app)
oauth = OAuth(app)
app.register_blueprint(search)

app.register_blueprint(author)

app.register_blueprint(department)

app.register_blueprint(authentication)


# OAuth config
google =  oauth.register(
    name='google',
    client_id=GOOGLE_CLIENT_ID,
    client_secret=GOOGLE_CLIENT_SECRET,
    access_token_url=GOOGLE_TOKEN_URI,
    access_token_params=None,
    authorize_url=GOOGLE_AUTH_URI,
    authorize_params=None,
    api_base_url='https://www.googleapis.com/oauth2/v1/',
    client_kwargs={'scope': 'openid profile email https://www.googleapis.com/auth/spreadsheets'}
)

REFRESH_TOKEN = ""

@app.route('/login_google')
def login_google():
    google = oauth.create_client('google')
    redirect_url = url_for('authorize', _external=True)
    return google.authorize_redirect(redirect_url)

@app.route('/authorize')
def authorize():
    google = oauth.create_client('google')
    token = google.authorize_access_token()
    REFRESH_TOKEN = AccessTokenCredentials(token['access_token'], None)
    print (token)
    resp = google.get('userinfo')
    user_info = resp.json()    
    session['email'] = user_info['email']
    return redirect('/search')

@app.route('/download', methods=['GET','POST'])
def download():
    search_id = request.args.get('search_id')
    citation_data = mysql_to_dataframe("SELECT some stuff", (search_id,))
    gc = gspread.authorize(REFRESH_TOKEN)
    sh = gc.create('pubmed_citations')
    sh.update([citation_data.columns.values.tolist()] + citation_data.values.tolist())
    return redirect('/search')

if __name__ == '__main__':
    app.run(host='127.0.0.1', port=8080, debug=True)

I can successfully authenticate using OAuth by going to the /login_google route and then it'll go to /authorize That will take my back to my application, however I want to create a new spreadsheet for my endusers whenever they go to /download but I just can't authenticate gspread using any article I've found over the internet please help me