code: def test_no_operator_loaded():
      mop = ImageMorph.MorphOp()
      with pytest.raises(Exception) as e:
          mop.apply(None)
      assert str(e.value) == "No operator loaded"
      with pytest.raises(Exception) as e:
          mop.match(None)
      assert str(e.value) == "No operator loaded"
      with pytest.raises(Exception) as e:
          mop.save_lut(None)
      assert str(e.value) == "No operator loaded"
  
imports: from __future__ import annotations
  import pytest
  from PIL import Image, ImageMorph, _imagingmorph
  from .helper import assert_image_equal_tofile, hopper
label_desc: Use image node_id 7 for calling a global function with example usage: test_no_operator_loaded() without return types