code: def test_nan_image():
      img = np.ones((10, 10))
      img[0, 0] = np.nan
      iv = pg.ImageView()
      iv.setImage(img)
      iv.show()
      iv.getImageItem().getHistogram()
      app.processEvents()
      iv.window().close()
  
imports: import numpy
  import pyqtgraph
label_desc: Use image node_id 1 for calling a global function with example usage: test_nan_image() without return types