How to redirect to External Url in flask?

I'm new to Python and Flask and I'm trying to do the equivalent of Response.redirect as in C# - ie: redirect to a specific external Domain URL with appending string - how do I go about this?

import os
from flask import Flask
import flask
import urllib

app = Flask(__name__)

# Registers url to run before each request
@app.before_request
def before_request():
    return _redirectSSO(flask.request)


def _redirectSSO(reuested_url):
    # External Domain SSO URL to authenticate user
    url = 'https://ssologon/ssologinconfirm.html?target={0}'.format(urllib.quote_plus(reuested_url))

    return flask.redirect(url)

@app.route('/')
def hello():
    return "Hello World"

Please standardize/optimize the code, to make it work with out any issues?Thans