code: def test_label_scope():
      from nni.nas.nn.pytorch.base import strict_label_scope
  
      with strict_label_scope("_unused_"):
          with pytest.raises(ValueError, match="Label"):
              Categorical([1, 2, 3])
          assert Categorical([1, 2, 3], label="x").label == "x"
          with label_scope("hello"):
              assert auto_label() == "hello/1"
              assert (
                  Categorical([1, 2, 3], label="x").label == "hello/x"
              )
  
imports: import copy
  import pytest
  import torch
  import nni
  from torch import nn
  from nni.common.serializer import is_traceable
  from nni.mutable import Categorical, ExpressionConstraint, ensure_frozen, frozen_context, label_scope, auto_label, SampleMissingError
  from nni.mutable.mutable import _mutable_equal
  from nni.nas.nn.pytorch import ModelSpace, MutableModule, ParametrizedModule
  from nni.nas.space import model_context
label_desc: Use image node_id 1 for calling a global function with example usage: test_label_scope() without return types