code: def test_quadmesh_nodata(self):
      arr = np.array([[0, 1, 2], [3, 4, 5]])
      qmesh = QuadMesh(Image(arr)).opts(nodata=0)
      plot = mpl_renderer.get_plot(qmesh)
      artist = plot.handles["artist"]
      if mpl38:
          expected = np.array([[3, 4, 5], [np.nan, 1, 2]])
      else:
          expected = np.array([3, 4, 5, np.nan, 1, 2])
  
      np.testing.assert_equal(artist.get_array().data, expected)
  
file_path: holoviews/holoviews/tests/plotting/matplotlib/test_quadmeshplot.py
imports: import numpy
  from holoviews.element import Dataset, Image, QuadMesh
  from .test_plot import TestMPLPlot, mpl38, mpl_renderer
label_desc: Use image node_id 2 for calling the TestQuadMeshPlot obj's underlying member method code with example usage: obj.test_quadmesh_nodata() without return types