bpo-42360: Add advice to help avoid pickling issues. (GH-23305)

diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index f538da5e1c9faafb79beed073bfc915abc039b87..1293f542b04377e15e662355c0ddb07e5a2c6b35 100644 (file)
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -862,6 +862,9 @@ they add the ability to access fields by name instead of position index.
     Named tuple instances do not have per-instance dictionaries, so they are
     lightweight and require no more memory than regular tuples.
 
+    To support pickling, the named tuple class should be assigned to a variable
+    that matches *typename*.
+
     .. versionchanged:: 3.1
        Added support for *rename*.