diff -r 87d76ce01217 Doc/library/stdtypes.rst
--- a/Doc/library/stdtypes.rst	Fri Nov 04 17:07:47 2016 -0400
+++ b/Doc/library/stdtypes.rst	Fri Nov 04 17:02:15 2016 -0500
@@ -202,7 +202,8 @@
    operator: not in
 
 Two more operations with the same syntactic priority, :keyword:`in` and
-:keyword:`not in`, are supported only by sequence types (below).
+:keyword:`not in`, are supported by types that are iterable or implement
+the :meth:`__contains__` method.
 
 
 .. _typesnumeric: