code: def test_stack():
      a = [1, 2, 3]
      b = [4, 5, 6]
      c = [7, 8, 9]
      ret = StackCollator()((a, b, c))
      assert torch.all(
          ret == torch.as_tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
      )
  
imports: import torch
  from autogluon.multimodal.data.collator import DictCollator, ListCollator, PadCollator, StackCollator, TupleCollator
label_desc: Use image node_id 1 for calling a global function with example usage: test_stack() without return types