diff --git a/Lib/copy.py b/Lib/copy.py
index 0180554..77b7ad3 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -301,7 +301,10 @@
     if state:
         if deep:
             state = deepcopy(state, memo)
-        y.__dict__.update(state)
+        if hasattr(y, '__setstate__'):
+            y.__setstate__(state)
+        else:
+            y.__dict__.update(state)
     return y
 
 del d