Add missing target.
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 7a56554..c0ed140 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -1694,6 +1694,8 @@
             yield arg
 
 
+.. _argparse-from-optparse:
+
 Upgrading optparse code
 -----------------------