code: def authorize_view(self):
          
          args = request.args.to_dict()
  
          # Scopes will be passed as mutliple args, and to_dict() will only
          # return one. So, we use getlist() to get all of the scopes.
          args['scopes'] = request.args.getlist('scopes')
  
          return_url = args.pop('return_url', None)
          if return_url is None:
              return_url = request.referrer or '/'
  
          flow = self._make_flow(return_url=return_url, **args)
          auth_url = flow.step1_get_authorize_url()
  
          return redirect(auth_url)
docs: Flask view that starts the authorization flow.
  
          Starts flow by redirecting the user to the OAuth2 provider.