python · priyanshu2282-cyber · Jan 28, 2026 · Jan 28, 2026
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
@@ -4764,6 +4764,11 @@ def test_deprecated_version(self):
        ) as cm:
                getattr(ET, "VERSION")
        self.assertEqual(cm.filename, __file__)
+
+    def test_subelement_parent_positional_only(self):
+        root = ET.Element("root")
+        with self.assertRaises(TypeError):
+            ET.SubElement(root, "child", parent="0")


 # --------------------------------------------------------------------

diff --git a/Misc/NEWS.d/next/Library/2026-01-28-20-06-13.gh-issue-144270.Whq3TD.rst b/Misc/NEWS.d/next/Library/2026-01-28-20-06-13.gh-issue-144270.Whq3TD.rst
@@ -0,0 +1 @@
+Fix xml.etree.ElementTree.SubElement to reject ``parent`` passed as a keyword argument, making the Python signature consistent with the C implementation.
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
@@ -611,6 +611,13 @@ subelement(PyObject *self, PyObject *args, PyObject *kwds)
    ElementObject* parent;
    PyObject* tag;
    PyObject* attrib = NULL;
+    if (kwds && PyDict_Contains(kwds, PyUnicode_FromString("parent"))) {
+        PyErr_SetString(
+            PyExc_TypeError,
+            "SubElement() got some positional-only arguments passed as keyword arguments"
+        );
+         return NULL;
+    }
    if (!PyArg_ParseTuple(args, "O!O|O!:SubElement",
                          st->Element_Type, &parent, &tag,
                          &PyDict_Type, &attrib)) {
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Fix xml.etree.ElementTree.SubElement to reject ``parent`` passed as a keyword argument, making the Python signature consistent with the C implementation.