code: def simple_model():
      return _create_simple_model()
  
imports: import copy
  import pytest
  import torch
  import torch.functional
  import torch.nn
  from coremltools.optimize.torch.palettization import DKMPalettizer, DKMPalettizerConfig
  from coremltools.optimize.torch.palettization.palettization_config import DEFAULT_PALETTIZATION_SCHEME
  from coremltools.test.optimize.torch.palettization.palettization_utils import _assert_changes_post_attach, _assert_changes_post_prepare
label_desc: Use image node_id 2 for calling a global function with example usage: simple_model() and returns: _create_simple_model