bpo-40651: Improve LRU recipe in the OrderedDict documentation (GH-#20139)

diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index c9533a3cb8f488562020bd3a32161392cacf0692..549ac1bccadf5de92349b7c46a180326a33ced69 100644 (file)
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -1161,6 +1161,8 @@ variants of :func:`functools.lru_cache`::
             return value
 
         def __setitem__(self, key, value):
+            if key in self:
+                self.move_to_end(key)
             super().__setitem__(key, value)
             if len(self) > self.maxsize:
                 oldest = next(iter(self))