code: def test_set_placeholder():
      data = [
          {"frozen-vm-1": ["0000:3b:00.0", "0000:3b:00.1"]},
          {"frozen-vm-2": ["0000:3b:00.3", "0000:3b:00.4"]},
      ]
      place_holder_number = 3
      expected_result = [
          {"frozen-vm-1": ["0000:3b:00.0", "0000:3b:00.1"]},
          {"frozen-vm-2": ["0000:3b:00.3", "0000:3b:00.4"]},
          {},
          {},
          {},
      ]
  
      set_gpu_placeholder(data, place_holder_number)
      assert data == expected_result
  
imports: import copy
  import time
  import pytest
  import threading
  from unittest.mock import MagicMock, patch
  from ray.autoscaler._private.vsphere.node_provider import VsphereNodeProvider
  from ray.autoscaler._private.vsphere.config import update_vsphere_configs, validate_frozen_vm_configs
  from ray.autoscaler._private.vsphere.gpu_utils import split_vm_2_gpu_cards_map, GPUCard, set_gpu_placeholder
  from ray.autoscaler._private.vsphere.utils import singleton_client
label_desc: Use image node_id 11 for calling a global function with example usage: test_set_placeholder() without return types