add a docstring for not_

1 files changed, 34 insertions, 0 deletions

diff --git a/pyramid/config/util.py b/pyramid/config/util.py
index a98e71cf5..892592196 100644
--- a/pyramid/config/util.py
+++ b/pyramid/config/util.py
@@ -29,6 +29,40 @@ def as_sorted_tuple(val):
     return val
 
 class not_(object):
+    """
+
+    You can invert the meaning of any predicate value by wrapping it in a call
+    to :class:`pyramid.config.not_`.
+
+    .. code-block:: python
+       :linenos:
+
+       from pyramid.config import not_
+
+       config.add_view(
+           'mypackage.views.my_view',
+           route_name='ok', 
+           request_method=not_('POST')
+           )
+
+    The above example will ensure that the view is called if the request method
+    is *not* ``POST``, at least if no other view is more specific.
+
+    This technique of wrapping a predicate value in ``not_`` can be used
+    anywhere predicate values are accepted:
+
+    - :meth:`pyramid.config.Configurator.add_view`
+
+    - :meth:`pyramid.config.Configurator.add_route`
+
+    - :meth:`pyramid.config.Configurator.add_subscriber`
+
+    - :meth:`pyramid.view.view_config`
+
+    - :meth:`pyramid.events.subscriber`
+
+    .. versionadded:: 1.5
+    """
     def __init__(self, value):
         self.value = value