code: def test_misssing_data(self, toy_df):
      df = pd.DataFrame(
          {
              "x": [0, 0, 0],
              "y": [2, np.nan, 1],
              "baseline": [0, 0, 0],
          }
      )
      res = Stack()(df, None, "x", {})
      assert_array_equal(res["y"], [2, np.nan, 3])
      assert_array_equal(res["baseline"], [0, np.nan, 2])
  
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 3 for calling the TestStack obj's underlying member method code with example usage: obj.test_misssing_data(toy_df) without return types