new_contents: #!/usr/bin/env python3
  # Install dependencies with:
  # pip install flask requests requests_oauth2
  import os
  import logging
  import requests
  
  from requests_oauth2.services import GoogleClient
  from requests_oauth2 import OAuth2BearerToken
  from flask import Flask, request, redirect, session
  
  
  app = Flask(__name__)
  app.secret_key = os.environ.get("SECRET_KEY") or os.urandom(20)
  
  
  google_auth = GoogleClient(
      client_id=("554229061086-np1qvffgq6gi1f6njg99qkeqt4h2gaut"
                 ".apps.googleusercontent.com"),
      client_secret="XqTsoS6DXq-W0KgTqvQISBOM",
      redirect_uri="http://localhost:5000/google/oauth2callback",
  )
  
  
  @app.route("/")
  def index():
      return redirect("/google/")
  
  
  @app.route("/google/")
  def google_index():
      if not session.get("access_token"):
          return redirect("/google/oauth2callback")
      with requests.Session() as s:
          s.auth = OAuth2BearerToken(session["access_token"])
          r = s.get("https://www.googleapis.com/plus/v1/people/me")
      r.raise_for_status()
      data = r.json()
      return "Hello, {}!".format(data["displayName"])
  
  
  @app.route("/google/oauth2callback")
  def google_oauth2callback():
      code = request.args.get("code")
      error = request.args.get("error")
      if error:
          return "error :( {!r}".format(error)
      if not code:
          return redirect(google_auth.authorize_url(
              scope=["profile", "email"],
              response_type="code",
          ))
      data = google_auth.get_token(
          code=code,
          grant_type="authorization_code",
      )
      session["access_token"] = data.get("access_token")
      return redirect("/")
  
  
  if __name__ == "__main__":
      logging.basicConfig(level=logging.DEBUG)
      app.run(debug=True)
  
subject: Add an example Flask app