code: def test_baseline_homogeneity_check(self, toy_df):
      toy_df["baseline"] = [0, 1, 2]
      groupby = GroupBy(["color", "group"])
      move = Stack()
      err = "Stack move cannot be used when baselines"
      with pytest.raises(RuntimeError, match=err):
          move(toy_df, groupby, "x", {})
  
imports: from itertools import product
  import numpy
  import pandas
  from pandas.testing import assert_series_equal
  from numpy.testing import assert_array_equal, assert_array_almost_equal
  from seaborn._core.moves import Dodge, Jitter, Shift, Stack, Norm
  from seaborn._core.rules import categorical_order
  from seaborn._core.groupby import GroupBy
  import pytest
label_desc: Use image node_id 4 for calling the TestStack obj's underlying member method code with example usage: obj.test_baseline_homogeneity_check(toy_df) without return types