code: func (*Service) ListMachines(c context.Context, req *crimson.ListMachinesRequest) (*crimson.ListMachinesResponse, error) {
  	machines, err := listMachines(c, database.Get(c), req)
  	if err != nil {
  		return nil, err
  	}
  	return &crimson.ListMachinesResponse{
  		Machines: machines,
  	}, nil
  }
docs: // ListMachines handles a request to list machines.