merge fix for issue #17953

brettcannon · brettcannon · commit 6489d0b3808e · 2013-05-24T17:31:37.000-04:00
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
@@ -757,6 +757,8 @@ always available.
 
    This is a dictionary that maps module names to modules which have already been
    loaded.  This can be manipulated to force reloading of modules and other tricks.
+   However, replacing the dictionary will not necessarily work as expected and
+   deleting essential items from the dictionary may cause Python to fail.
 
 
 .. data:: path
