code: func (s *Server) GetExtension(ctx context.Context, request *api.GetExtensionRequest) (*api.GetExtensionResponse, error) {
  	if request.ExtensionID == "" {
  		return nil, status.Errorf(codes.InvalidArgument, "extension ID must be provided")
  	}
  
  	var extension *api.Extension
  	s.store.View(func(tx store.ReadTx) {
  		extension = store.GetExtension(tx, request.ExtensionID)
  	})
  
  	if extension == nil {
  		return nil, status.Errorf(codes.NotFound, "extension %s not found", request.ExtensionID)
  	}
  
  	return &api.GetExtensionResponse{Extension: extension}, nil
  }
docs: // GetExtension returns a `GetExtensionResponse` with a `Extension` with the same
  // id as `GetExtensionRequest.extension_id`
  // - Returns `NotFound` if the Extension with the given id is not found.
  // - Returns `InvalidArgument` if the `GetExtensionRequest.extension_id` is empty.
  // - Returns an error if the get fails.