code: def main():
      """Requests placement of a GPU actor."""
  
      @ray.remote(num_gpus=1, num_cpus=1)
      class GPUActor:
          def where_am_i(self):
              assert len(ray.get_gpu_ids()) == 1
              return "on-a-gpu-node"
  
      GPUActor.options(name="gpu_actor", lifetime="detached").remote()
  
label_desc: Use image node_id 1 for calling a global function with example usage: main() and returns: str