code: def test_model_copy_with_loop():
      class MyShim(Shim):
          name = "testshim"
  
          def to_bytes(self):
              return test_replace_node_with_indirect_node_ref
  
          def from_bytes(self, bytes):
              pass
  
      model_a = create_model("a")
      working_shim = MyShim(None)
      layer = Model(
          "test",
          lambda X: (X, lambda dY: dY),
          dims={"nI": 5, "nO": 5},
          params={"W": numpy.zeros((10,)), "b": None},
          refs={"a": model_a, "b": None},
          attrs={"foo": "bar"},
          shims=[working_shim],
          layers=[model_a, model_a],
      )
      layer2 = Model(
          "test2",
          lambda X: (X, lambda dY: dY),
          dims={"nI": 5, "nO": 5},
          params={"W": numpy.zeros((10,)), "b": None},
          refs={"a": model_a, "b": None},
          attrs={"foo": "bar"},
          shims=[working_shim],
          layers=[model_a, model_a],
      )
      relu = Relu(5)
      model = chain(layer, relu, layer, layer2)
      model2 = model.copy()
      model.from_dict(model2.to_dict())
      assert model2.name == "test>>relu>>test>>test2"
      assert model2.layers[0] == model2.layers[2]
      assert id(model2.layers[0].shims[0]) == id(
          model2.layers[3].shims[0]
      )
  
imports: import threading
  import time
  from collections import Counter
  import numpy
  import pytest
  from thinc.api import Adam, CupyOps, Dropout, Linear, Model, Relu, Shim, Softmax, chain, change_attr_values, concatenate, set_dropout_rate, use_ops, with_debug, wrap_model_recursive
  from thinc.compat import has_cupy_gpu
  from ..util import make_tempdir
label_desc: Use image node_id 34 for calling a global function with example usage: test_model_copy_with_loop() and returns: test_replace_node_with_indirect_node_ref