Update test_composites.py

satpy/tests/test_composites.py

@@ -978,7 +978,7 @@ def test_cloud_compositor_validity_checks(self):
         """Test that errors are raised for invalid settings."""
         from satpy.composites import CloudCompositor
         with pytest.raises(ValueError, match="Invalid mode RGB.  Supported modes: LA, RGBA"):
-            res = CloudCompositor("test", mode="RGB")
+            _ = CloudCompositor("test", mode="RGB")
 
 
 class TestPrecipCloudsCompositor(unittest.TestCase):