code: func GoogleToken(file, clientID, clientSecret, scope string) (*oauth.Transport, error) {
  	cfg := &oauth.Config{
  		ClientId:     clientID,
  		ClientSecret: clientSecret,
  		Scope:        scope,
  		AuthURL:      "https://accounts.google.com/o/oauth2/auth",
  		TokenURL:     "https://accounts.google.com/o/oauth2/token",
  	}
  	return Token(file, cfg)
  }
docs: // GoogleToken is like Token but assumes the Google AuthURL and TokenURL,
  // so that only the client ID and secret and desired scope must be specified.