How to import gRPC empty and Google api annotations proto : <p>I am trying to use Google Cloud Endpoints to make a gRPC based api that can <a href="https://cloud.google.com/endpoints/docs/transcoding" rel="noreferrer">transcode incoming REST requests</a>. I am following <a href="https://github.com/GoogleCloudPlatform/python-docs-samples/blob/master/endpoints/bookstore-grpc/http_bookstore.proto" rel="noreferrer">their example code</a> but I can not any documentation on how to properly import and compile with the annotation.proto or the empty.proto.</p>

<p>Thank you!</p>
