- Issue #17477: Update the bsddb module to pybsddb 5.3.0, supporting
  db-5.x, and dropping support for db-4.1 and db-4.2.
diff --git a/Lib/bsddb/dbobj.py b/Lib/bsddb/dbobj.py
index c7c7322..1400fe1 100644
--- a/Lib/bsddb/dbobj.py
+++ b/Lib/bsddb/dbobj.py
@@ -30,12 +30,7 @@
     import db
 
 if sys.version_info < (2, 6) :
-    try:
-        from UserDict import DictMixin
-    except ImportError:
-        # DictMixin is new in Python 2.3
-        class DictMixin: pass
-    MutableMapping = DictMixin
+    from UserDict import DictMixin as MutableMapping
 else :
     import collections
     MutableMapping = collections.MutableMapping
@@ -196,6 +191,8 @@
         return self._cobj.set_bt_compare(*args, **kwargs)
     def set_cachesize(self, *args, **kwargs):
         return self._cobj.set_cachesize(*args, **kwargs)
+    def set_dup_compare(self, *args, **kwargs) :
+        return self._cobj.set_dup_compare(*args, **kwargs)
     def set_flags(self, *args, **kwargs):
         return self._cobj.set_flags(*args, **kwargs)
     def set_h_ffactor(self, *args, **kwargs):