#5199: make warning about vars() assignment more visible.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 0497d45..c19462c 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1352,8 +1352,12 @@
Without arguments, return a dictionary corresponding to the current local symbol
table. With a module, class or class instance object as argument (or anything
else that has a :attr:`__dict__` attribute), returns a dictionary corresponding
- to the object's symbol table. The returned dictionary should not be modified:
- the effects on the corresponding symbol table are undefined. [#]_
+ to the object's symbol table.
+
+ .. warning::
+
+ The returned dictionary should not be modified:
+ the effects on the corresponding symbol table are undefined. [#]_
.. function:: xrange([start,] stop[, step])