docs: def logout(session_id, **kwargs):
      """
          Logout a user, removing their cookie if it exists and returning 'OK'
  
  
          args:
              session_id (string): The session ID to identify the cookie to remove
          returns:
              'OK'
          raises:
              HydraError if the logout fails
      """
  
      hydra_session_object = session.SessionObject({}, #This is normally a request object, but in this case is empty
              validate_key=config.get('COOKIES', 'VALIDATE_KEY', 'YxaDbzUUSo08b+'),
              type='file',
              cookie_expires=True,
              data_dir=config.get('COOKIES', 'DATA_DIR', '/tmp'),
              file_dir=config.get('COOKIES', 'FILE_DIR', '/tmp/auth'))
  
      hydra_session = hydra_session_object.get_by_id(session_id)
  
      if hydra_session is not None:
          hydra_session.delete()
          hydra_session.save()
  
      return 'OK'