code: def check_gc():
      if Device.DEFAULT == "GPU":
          from extra.introspection import print_objects
  
          assert print_objects() == 0
  
imports: import unittest
  import time
  import numpy
  from tinygrad.nn.state import get_parameters
  from tinygrad.nn import optim
  from tinygrad.tensor import Device
  from tinygrad.helpers import getenv, CI
  from extra.training import train
  from extra.models.convnext import ConvNeXt
  from extra.models.efficientnet import EfficientNet
  from extra.models.transformer import Transformer
  from extra.models.vit import ViT
  from extra.models.resnet import ResNet18
label_desc: Use image node_id 2 for calling a global function with example usage: check_gc() without return types