diff --git a/Lib/test/libregrtest/refleak.py b/Lib/test/libregrtest/refleak.py
index 6724488..d68ea63 100644
--- a/Lib/test/libregrtest/refleak.py
+++ b/Lib/test/libregrtest/refleak.py
@@ -8,9 +8,13 @@
 try:
     from _abc import _get_dump
 except ImportError:
+    import weakref
+
     def _get_dump(cls):
-        # For legacy Python version
-        return (cls._abc_registry, cls._abc_cache,
+        # Reimplement _get_dump() for pure-Python implementation of
+        # the abc module (Lib/_py_abc.py)
+        registry_weakrefs = set(weakref.ref(obj) for obj in cls._abc_registry)
+        return (registry_weakrefs, cls._abc_cache,
                 cls._abc_negative_cache, cls._abc_negative_cache_version)