code: func expandCustomizationGuiRunOnce(d *schema.ResourceData) *types.CustomizationGuiRunOnce {
  	obj := &types.CustomizationGuiRunOnce{
  		CommandList: structure.SliceInterfacesToStrings(d.Get(cWindowsKeyPrefix + "." + "run_once_command_list").([]interface{})),
  	}
  	if len(obj.CommandList) < 1 {
  		return nil
  	}
  	return obj
  }
docs: // expandCustomizationGuiRunOnce reads certain ResourceData keys and
  // returns a CustomizationGuiRunOnce.