Google App Engineが OAuthをサポート、でも Googleアカウントの無いユーザーは使えない？

OAuth for Python Overview - Google App Engine - Google Code

The user must have a Google account to sign in and authorize a consumer. If an app uses federated logins (OpenID), the user is sent directly to Google Accounts to sign in to authorize a consumer. Other OpenID identity providers are not supported for OAuth authentication.

OAuthをGoogleアカウントと紐付けて認証するってこと？？？
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