bpo-38565: add new cache_parameters method for lru_cache (GH-16916)

1 files changed, 8 insertions, 0 deletions

diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst
index d3debac843..cedc3ad5ec 100644
--- a/Doc/library/functools.rst
+++ b/Doc/library/functools.rst
@@ -108,6 +108,11 @@ The :mod:`functools` module defines the following functions:
    cached separately.  For example, ``f(3)`` and ``f(3.0)`` will be treated
    as distinct calls with distinct results.
 
+   The wrapped function is instrumented with a :func:`cache_parameters`
+   function that returns a new :class:`dict` showing the values for *maxsize*
+   and *typed*.  This is for information purposes only.  Mutating the values
+   has no effect.
+
    To help measure the effectiveness of the cache and tune the *maxsize*
    parameter, the wrapped function is instrumented with a :func:`cache_info`
    function that returns a :term:`named tuple` showing *hits*, *misses*,
@@ -178,6 +183,9 @@ The :mod:`functools` module defines the following functions:
    .. versionchanged:: 3.8
       Added the *user_function* option.
 
+   .. versionadded:: 3.9
+      Added the function :func:`cache_parameters`
+
 .. decorator:: total_ordering
 
    Given a class defining one or more rich comparison ordering methods, this