An example's doctest directives modify doctest's behavior for that single
example. Use ``+`` to enable the named behavior, or ``-`` to disable it.
+.. note::
+ Due to an `unfortunate bug`_ in our documentation publishing process, the
+ directives in the following examples are not being displayed in the
+ rendered HTML version. Please use the "Show Source" link in the sidebar
+ to view the details of the directive usage examples.
+
+ .. _unfortunate bug: http://bugs.python.org/issue12947
+
For example, this test passes::
>>> print(list(range(20))) #doctest: +NORMALIZE_WHITESPACE