Add example for use cases requiring default values.
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index 89885ab..bdc0b86 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -492,6 +492,15 @@
>>> Point(x=10, y=20)
Point(10.000, 20.000)
+Default values can be implemented by starting with a prototype instance
+and customizing it with :meth:`__replace__`:
+
+::
+
+ >>> Account = namedtuple('Account', 'owner balance transaction_count')
+ >>> model_account = Account('<owner name>', 0.0, 0)
+ >>> johns_account = model_account.__replace__(owner='John')
+
.. rubric:: Footnotes
.. [#] For information on the star-operator see