code: def test_nightshade_image():
      # Test the actual creation of the image
      ax = plt.axes(projection=ccrs.PlateCarree())
      ax.coastlines()
      dt = datetime(2018, 11, 10, 0, 0)
      ax.set_global()
      ax.add_feature(Nightshade(dt, alpha=0.75))
      return ax.figure
  
imports: from datetime import datetime
  import matplotlib.pyplot
  import pytest
  import cartopy.crs
  from cartopy.feature.nightshade import Nightshade
label_desc: Use image node_id 1 for calling a global function with example usage: test_nightshade_image() and returns: ax