code: def test_marker_with_nan():
      # This creates a marker with nans in it, which was segfaulting the
      # Agg backend (see #3722)
      fig, ax = plt.subplots(1)
      steps = 1000
      data = np.arange(steps)
      ax.semilogx(data)
      ax.fill_between(data, data * 0.8, data * 1.2)
      buf = io.BytesIO()
      fig.savefig(buf, format="png")
  
imports: import io
  import numpy
  from numpy.testing import assert_array_almost_equal
  from PIL import Image, TiffTags
  import pytest
  from matplotlib import collections, patheffects, pyplot, transforms, rcParams, rc_context
  from matplotlib.backends.backend_agg import RendererAgg
  from matplotlib.figure import Figure
  from matplotlib.image import imread
  from matplotlib.path import Path
  from matplotlib.testing.decorators import image_comparison
  from matplotlib.transforms import IdentityTransform
label_desc: Use image node_id 3 for calling a global function with example usage: test_marker_with_nan() without return types