code: def test_parameters__reduce__(parameters):
      """Test the __reduce__ magic method."""
      pars, _, _ = parameters
      reduced = pars.__reduce__()
  
      assert isinstance(reduced[2], dict)
      assert "unique_symbols" in reduced[2].keys()
      assert reduced[2]["unique_symbols"]["b"] == 20
      assert "params" in reduced[2].keys()
      assert isinstance(reduced[2]["params"][0], lmfit.Parameter)
  
imports: from copy import copy, deepcopy
  import os
  import pickle
  import numpy
  from numpy.testing import assert_allclose
  import pytest
  import lmfit
  from lmfit.models import VoigtModel
label_desc: Use image node_id 14 for calling a global function with example usage: test_parameters__reduce__(parameters) without return types