[util] let a CustomNone instance be equal to itself

gallery_dl/util.py

@@ -540,10 +540,14 @@ class CustomNone():
     def __bool__():
         return False
 
+    def __eq__(self, other):
+        return self is other
+
+    def __ne__(self, other):
+        return self is not other
+
     __lt__ = true
     __le__ = true
-    __eq__ = false
-    __ne__ = true
     __gt__ = false
     __ge__ = false
 

test/test_util.py

@@ -755,8 +755,9 @@ def hash(value):
 
         self.assertLess(obj, "foo")
         self.assertLessEqual(obj, None)
-        self.assertFalse(obj == obj)
-        self.assertTrue(obj != obj)
+        self.assertTrue(obj == obj)
+        self.assertFalse(obj == 0)
+        self.assertFalse(obj != obj)
         self.assertGreater(123, obj)
         self.assertGreaterEqual(1.23, obj)