old_contents: from jupyterhub.auth import LocalAuthenticator
  from .oidc import OidcAuthenticator
  
  class MeQuantaOidcAuthenticator(OidcAuthenticator):
      login_service = "MeQuanta"
      oidc_provider_url = 'http://identity2.mequanta.com'
      oidc_callback_url = 'https://localhost:8000/hub/oidc_callback'
      client_id_env = 'MEQUANTA_CLIENT_ID'
      client_secret_env = 'MEQUANTA_CLIENT_SECRET'
  
  class LocalMeQuantaOidcAuthenticator(LocalAuthenticator, MeQuantaOidcAuthenticator):
      pass
      
  
new_contents: from jupyterhub.auth import LocalAuthenticator
  from .oidc import OidcAuthenticator
  import os
  from traitlets import Unicode
  from tornado import gen
  
  class MeQuantaOidcAuthenticator(OidcAuthenticator):
      login_service = "MeQuanta"
      oidc_provider_url = 'http://identity2.mequanta.com'
      oidc_callback_url = 'https://localhost:8000/hub/oidc_callback'
      client_id_env = 'MEQUANTA_CLIENT_ID'
      client_secret_env = 'MEQUANTA_CLIENT_SECRET'
      fixed_user_env = 'MEQUANTA_FIXED_USER'
      fixed_user = Unicode(config=True)
      def _fixed_user_default(self):
          return os.getenv(self.fixed_user_env, None)
  
      @gen.coroutine
      def authenticate(self, handler):
          username = super(MeQuantaOidcAuthenticator, self).authenticate(handler)
          if username is not None and self.fixed_user is not None:
              username = self.fixed_user
          return username
  
  class LocalMeQuantaOidcAuthenticator(LocalAuthenticator, MeQuantaOidcAuthenticator):
      pass
      
  
subject: add fixed_user options