code: def test_missing_semantic_data(self, prop):
      x = [1, 2, 3]
      y = [5, 3, 4]
      z = ["a", float("nan"), "b"]
  
      p = Plot(x=x, y=y, **{prop: z}).add(Dot()).plot()
      ax = p._figure.axes[0]
      (points,) = ax.collections
      self.check_offsets(points, [1, 3], [5, 4])
  
imports: from matplotlib.colors import to_rgba, to_rgba_array
  import pytest
  from numpy.testing import assert_array_equal
  from seaborn.palettes import color_palette
  from seaborn._core.plot import Plot
  from seaborn._marks.dot import Dot, Dots
label_desc: Use image node_id 4 for calling the TestDot obj's underlying member method code with example usage: obj.test_missing_semantic_data(prop) without return types