docs: def authenticate_user(self):
          """Confirm user authentication
  
          Make sure the user has provided all of the authentication
          info we need.
          """
          cloud_config = os_client_config.OpenStackConfig().get_one_cloud(
              cloud=self.options.os_cloud, argparse=self.options,
              network_api_version=self.api_version,
              verify=not self.options.insecure)
          verify, cert = cloud_config.get_requests_verify_args()
  
          # TODO(singhj): Remove dependancy on HTTPClient
          # for the case of token-endpoint authentication
  
          # When using token-endpoint authentication legacy
          # HTTPClient will be used, otherwise SessionClient
          # will be used.
          if self.options.os_token and self.options.os_url:
              auth = None
              auth_session = None
          else:
              auth = cloud_config.get_auth()
  
              auth_session = session.Session(
                  auth=auth, verify=verify, cert=cert,
                  timeout=self.options.http_timeout)
  
          interface = self.options.os_endpoint_type or self.endpoint_type
          if interface.endswith('URL'):
              interface = interface[:-3]
          self.client_manager = clientmanager.ClientManager(
              retries=self.options.retries,
              raise_errors=False,
              session=auth_session,
              url=self.options.os_url,
              token=self.options.os_token,
              region_name=cloud_config.get_region_name(),
              api_version=cloud_config.get_api_version('network'),
              service_type=cloud_config.get_service_type('network'),
              service_name=cloud_config.get_service_name('network'),
              endpoint_type=interface,
              auth=auth,
              insecure=not verify,
              log_credentials=True)
          return