bpo-36144: Add union operators to WeakValueDictionary584 (#19127)

Lib/weakref.py

@@ -310,6 +310,25 @@ class WeakValueDictionary(_collections_abc.MutableMapping):
             self._commit_removals()
         return list(self.data.values())
 
+    def __ior__(self, other):
+        self.update(other)
+        return self
+
+    def __or__(self, other):
+        if isinstance(other, _collections_abc.Mapping):
+            c = self.copy()
+            c.update(other)
+            return c
+        return NotImplemented
+
+    def __ror__(self, other):
+        if isinstance(other, _collections_abc.Mapping):
+            c = self.__class__()
+            c.update(other)
+            c.update(self)
+            return c
+        return NotImplemented
+
 
 class KeyedRef(ref):
     """Specialized reference that includes a key corresponding to the value.