400 error at chat api media.download

In the chat API, there is an error causing return of http 400 for any use of the media.download API.

Steps to reproduce:
1) Get a valid resource ID for an uploaded attachment from chat.messages.attachment.get
2) Feed into media.download API

I believe the error is due to a mistake in the URL. Per https://developers.google.com/chat/api/reference/rest/v1/media/download and https://developers.google.com/chat/how-tos/get-attachment it may need to have "?alt=media" appended to the end of the URL to support download.