diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -653,7 +653,7 @@
 
     def __contains__(self, value):
         for v in self:
-            if v == value:
+            if v is value or v == value:
                 return True
         return False
 
@@ -666,13 +666,13 @@
            Raises ValueError if the value is not present.
         '''
         for i, v in enumerate(self):
-            if v == value:
+            if v is value or v == value:
                 return i
         raise ValueError
 
     def count(self, value):
         'S.count(value) -> integer -- return number of occurrences of value'
-        return sum(1 for v in self if v == value)
+        return sum(1 for v in self if v is value or v == value)
 
 Sequence.register(tuple)
 Sequence.register(str)