How to connect to GoogleApps provider named "Google_Apps" in AWS via saml2aws

Question

I am trying to use saml2aws to authenticate to aws via GoogleApps/SAML. My configuration seems to be correct, or very nearly so, in that the "aws login" command correctly prompts for my google e-mail, password, presents a captcha url and accepts valid captcha text, and finally prompts for the role.

However, the end result of the "aws login" command is this error:

Requesting AWS credentials using SAML assertion.
Error logging into AWS role using SAML assertion.: Error retrieving STS credentials using SAML.: InvalidIdentityToken: Specified provider doesn't exist (Service: AWSOpenIdDiscoveryService; Status Code: 400; Error Code: AuthSamlManifestNotFoundException; Request ID: {{XXX}; Proxy: null)
status code: 400, request id: {{xxx}}

The specified provider in the configuration file is 'GoogleApps'. In AWS, the provider may be named incorrectly (?) as "Google_Apps". But if I attempt to set the provider in the configuration file as "Google_Apps" the login command immediately fails as an invalid provider (without prompting for any other login details).