+ """
+ :class:`Navigation` represents a group of :class:`NavigationItem`\ s that have an intrinsic relationship in terms of navigating a website. For example, a ``main`` navigation versus a ``side`` navigation, or a ``authenticated`` navigation versus an ``anonymous`` navigation.
+
+ A :class:`Navigation`'s :class:`NavigationItem`\ s will be accessible from its related :class:`.Node` and that :class:`.Node`'s descendants through a :class:`NavigationMapper` instance at :attr:`Node.navigation`. Example::
+
+ >>> node.navigation_set.all()
+ []
+ >>> parent = node.parent
+ >>> items = parent.navigation_set.get(key='main').roots.all()
+ >>> parent.navigation["main"] == node.navigation["main"] == list(items)
+ True
+
+ """
+ #: A :class:`NavigationManager` instance.