diff --git a/python/builtins.py b/python/builtins.py
index a906ddf6..104ab3d7 100644
--- a/python/builtins.py
+++ b/python/builtins.py
@@ -239,6 +239,11 @@ class set:
         if not isinstance(other, set):
             return NotImplemented
         return len(self ^ other) == 0
+    
+    def __ne__(self, other):
+        if not isinstance(other, set):
+            return NotImplemented
+        return len(self ^ other) != 0
 
     def isdisjoint(self, other):
         return len(self & other) == 0
diff --git a/python/cmath.py b/python/cmath.py
index 1d796d82..d45b9ec4 100644
--- a/python/cmath.py
+++ b/python/cmath.py
@@ -30,6 +30,12 @@ class complex:
             return self.real == other and self.imag == 0
         return NotImplemented
     
+    def __ne__(self, other):
+        res = self == other
+        if res is NotImplemented:
+            return res
+        return not res
+    
     def __add__(self, other):
         if type(other) is complex:
             return complex(self.real + other.real, self.imag + other.imag)
diff --git a/python/datetime.py b/python/datetime.py
index e7ad4f4c..ce5a35ed 100644
--- a/python/datetime.py
+++ b/python/datetime.py
@@ -10,12 +10,12 @@ class timedelta:
         return f"datetime.timedelta(days={self.days}, seconds={self.seconds})"
 
     def __eq__(self, other: 'timedelta') -> bool:
-        if type(other) is not timedelta:
+        if not isinstance(other, timedelta):
             return NotImplemented
         return (self.days, self.seconds) == (other.days, other.seconds)
 
     def __ne__(self, other: 'timedelta') -> bool:
-        if type(other) is not timedelta:
+        if not isinstance(other, timedelta):
             return NotImplemented
         return (self.days, self.seconds) != (other.days, other.seconds)