The
         
          google.appengine.api.users
         
         package provides the following exception classes:
        
- exception Error ()
- 
          This is the base class for all exceptions in this package. 
- exception UserNotFoundError ()
- 
          Raised by the User constructor if no email_address is provided and the current user is not logged in. 
- exception RedirectTooLongError ()
- 
          The redirect URL given to create_login_url() or create_logout_url() exceeds the maximum allowed length for a redirect URL. 
- exception NotAllowedError ()
- 
          The federated_identityparameter was given to create_login_url() , butFedereated Loginis not set. If you are getting this error you may need to change theAuthentication OptionstoFederated Loginin the Application Settings .