[util] make NONE compare equal to the native None

gallery_dl/util.py

@@ -681,10 +681,10 @@ class CustomNone():
         raise StopIteration
 
     def __eq__(self, other):
-        return self is other
+        return other is self or other is None
 
     def __ne__(self, other):
-        return self is not other
+        return other is not self and other is not None
 
     __lt__ = true
     __le__ = true

test/test_util.py

@@ -882,6 +882,12 @@ value = 123
         obj = util.NONE
 
         self.assertFalse(obj)
+        self.assertEqual(obj, obj)
+        self.assertEqual(obj, None)
+        self.assertNotEqual(obj, False)
+        self.assertNotEqual(obj, 0)
+        self.assertNotEqual(obj, "")
+
         self.assertEqual(len(obj), 0)
         self.assertEqual(int(obj), 0)
         self.assertEqual(hash(obj), 0)