Issue 21479: Fix markup for the TarFile.open() classmethod.
diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
index 740b185..1ef2703 100644
--- a/Doc/library/tarfile.rst
+++ b/Doc/library/tarfile.rst
@@ -292,7 +292,7 @@
    will be added as a pax global header if *format* is :const:`PAX_FORMAT`.
 
 
-.. method:: TarFile.open(...)
+.. classmethod:: TarFile.open(...)
 
    Alternative constructor. The :func:`tarfile.open` function is actually a
    shortcut to this classmethod.