Python Protobuffer GRPC assign to nested type and assign to repeated types

python_grpc.py

    obj1 = proto.Object.Detection()
    obj1.classname= classname
    bbox = proto.BoundingBox()
    bbox.X1 =1
    # Use CopyFrom to assign to nested element
    obj1.boundingbox.CopyFrom(bbox)
    obj1.object_id = random.randint(1, 6)
    
    callback = proto.Object()
    # use Extend to add to repeated elements
    callback.Objects.extend([obj1,])
    callback.media_id = int(id)
    callback.frame_id = int(id)

snippet.proto

message Object {
    message Detection {
        string classname = 1 ;
        BoundingBox boundingbox =2 ;
        int32 object_id =5;
    }
    repeated Detection Objects = 2 ;
    double detected_time =3 ;
    int32 media_id = 4 ;
    int32 frame_id = 5 ;
}