Issue #12442: add shutil.disk_usage()
diff --git a/Doc/library/shutil.rst b/Doc/library/shutil.rst
index 1a878d5..88c0eaa 100644
--- a/Doc/library/shutil.rst
+++ b/Doc/library/shutil.rst
@@ -164,6 +164,14 @@
    If the destination is on the current filesystem, then simply use rename.
    Otherwise, copy src (with :func:`copy2`) to the dst and then remove src.
 
+.. function:: disk_usage(path)
+
+   Return disk usage statistics about the given path as a namedtuple including
+   total, used and free space expressed in bytes.
+
+   .. versionadded:: 3.3
+
+   Availability: Unix, Windows.
 
 .. exception:: Error