code: def test_two_semantics(self, df):
      groupby = GroupBy(["x", "grp2", "grp3"])
      res = Dodge()(df, groupby, "x", {})
  
      levels = categorical_order(df["grp2"]), categorical_order(
          df["grp3"]
      )
      w, n = 0.8, len(levels[0]) * len(levels[1])
  
      shifts = np.linspace(0, w - w / n, n)
      shifts -= shifts.mean()
  
      assert_series_equal(res["y"], df["y"])
      assert_series_equal(res["width"], df["width"] / n)
  
      for (v2, v3), shift in zip(product(*levels), shifts):
          rows = (df["grp2"] == v2) & (df["grp3"] == v3)
          assert_series_equal(
              res.loc[rows, "x"], df.loc[rows, "x"] + shift
          )
  
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 13 for calling the TestDodge obj's underlying member method code with example usage: obj.test_two_semantics(df) without return types