Use get() instead of pop() for the optimized version of _replace().
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index e797296..fb9b958 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -531,7 +531,7 @@
>>> class Point(namedtuple('Point', 'x y')):
_make = classmethod(tuple.__new__)
def _replace(self, _map=map, **kwds):
- return self._make(_map(kwds.pop, ('x', 'y'), self))
+ return self._make(_map(kwds.get, ('x', 'y'), self))
Default values can be implemented by using :meth:`_replace` to
customize a prototype instance::