code: def test_model_space_label():
      class MyModelSpace(ModelSpace, label_prefix="backbone"):
          def __init__(self):
              super().__init__()
  
              self.choice = self.add_mutable(
                  nni.choice("depth", [2, 3, 4])
              )
  
      model = MyModelSpace()
      assert model.choice.label == "backbone/depth"
  
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 10 for calling a global function with example usage: test_model_space_label() without return types