Finish() called twice

JupyterHub
1

from jupyterhub.auth import Authenticator

import os


class CustomAuthenticator(Authenticator):
  auth_url = 'https://'
  jwt_token = 'token'

  def authenticate(self, handler, data):
    url = self.auth_url
    headers = {
        'Authorization': f'Bearer {self.jwt_token}'
    }

    response = requests.get(url, headers=headers)

    print("Authentication request sent.")
    print("Response JSON:", response.json())
    print("--------response----------", response.headers.get('Content-Type'))

    if response.status_code == 200:
        print("Authentication successful.")
        content_type = response.headers.get('Content-Type', '')
        user_info = response.json() 
           
        username = next((claim['value'] for claim in user_info if claim['type'] == 'http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name'), None)

        if username:
            print("Authenticated username:", username)
            redirect_url = "/spawn"
            # print("Redirecting to:", redirect_url)
            request.redirect(redirect_url) 
            
            return  # Ensure no further processing occurs
        else:
            print("Username not found in the response.")
            return None
    else:
        print("Authentication failed.")
        return None

c.JupyterHub.authenticator_class = CustomAuthenticator

c.JupyterHub.xsrf_cookies = True 

After login need to redirect to next page that is not happening getting some errors

super().finish(*args, **kwargs) File “/usr/local/lib/python3.12/site-packages/tornado/web.py”, line 1205, in finish raise RuntimeError(“finish() called twice”) RuntimeError: finish() called twice