code: def test_nan_isolated_points():
      y0 = [0, np.nan, 2, np.nan, 4, 5, 6]
      y1 = [np.nan, 7, np.nan, 9, 10, np.nan, 12]
  
      fig, ax = plt.subplots()
  
      ax.plot(y0, "-o")
      ax.plot(y1, "-o")
  
imports: import re
  import numpy
  from numpy.testing import assert_array_equal
  import pytest
  from matplotlib import patches
  from matplotlib.path import Path
  from matplotlib.patches import Polygon
  from matplotlib.testing.decorators import image_comparison
  import matplotlib.pyplot
  from matplotlib import transforms
  from matplotlib.backend_bases import MouseEvent
label_desc: Use image node_id 19 for calling a global function with example usage: test_nan_isolated_points() without return types