diff --git a/khard/carddav_object.py b/khard/carddav_object.py
index 67cb979..77f9ddb 100644
--- a/khard/carddav_object.py
+++ b/khard/carddav_object.py
@@ -39,6 +39,8 @@
 def multi_property_key(item: str) -> Tuple[Literal[0], str]: ...
 @overload
 def multi_property_key(item: Dict[T, Any]) -> Tuple[Literal[1], T]: ...
+@overload
+def multi_property_key(item: Union[str, Dict[T, Any]]) -> Tuple[Union[Literal[0], Literal[1]], Union[str, T]]: ...
 def multi_property_key(item: Union[str, Dict[T, Any]]
                        ) -> Tuple[int, Union[T, str]]:
     """Key function to pass to sorted(), allowing sorting of dicts with lists
diff --git a/test/test_carddav_object.py b/test/test_carddav_object.py
index 8833272..3e06e8e 100644
--- a/test/test_carddav_object.py
+++ b/test/test_carddav_object.py
@@ -6,7 +6,7 @@
 import unittest
 from unittest import mock
 
-from khard.carddav_object import CarddavObject
+from khard.carddav_object import CarddavObject, multi_property_key
 
 
 class CarddavObjectFormatDateObject(unittest.TestCase):
@@ -57,3 +57,28 @@ def test_parsing_base64_ecoded_photo_vcard_v4(self):
         self.assertEqual(uri_stuff, 'data:image/png;base64')
         data = base64.decodebytes(data.encode())
         self.assertEqual(data[:8], self.PNG_HEADER)
+
+
+class MultiPropertyKey(unittest.TestCase):
+    """Test for the multi_property_key helper function"""
+
+    def test_strings_are_in_the_first_sort_group(self) -> None:
+        group, _key = multi_property_key("some string")
+        self.assertEqual(group, 0)
+
+    def test_dicts_are_in_the_second_sort_group(self) -> None:
+        group, _key = multi_property_key({"some": "dict"})
+        self.assertEqual(group, 1)
+
+    def test_strings_are_their_own_keys(self) -> None:
+        _group, key = multi_property_key("some string")
+        self.assertEqual(key, "some string")
+
+    def test_dicts_are_keyed_by_the_first_key(self) -> None:
+        _group, key = multi_property_key({"some": "dict", "more": "stuff"})
+        self.assertEqual(key, "some")
+
+    def test_all_strings_are_sorted_before_dicts(self) -> None:
+        my_list = ["a", {"c": "d"}, "e", {"f": "g"}]
+        my_list.sort(key=multi_property_key)
+        self.assertEqual(my_list, ["a", "e", {"c": "d"}, {"f": "g"}])
diff --git a/test/test_yaml_editable.py b/test/test_yaml_editable.py
index 39fc56e..4238aba 100644
--- a/test/test_yaml_editable.py
+++ b/test/test_yaml_editable.py
@@ -95,3 +95,21 @@ def test_private_objects_can_have_an_ablabel(self) -> None:
         label.group = "1"
         result = ye._get_private_objects()
         self.assertEqual(result, {"foo": [{"baz": "bar"}]})
+
+    def test_private_objects_with_ablabels_are_sorted_by_ablabel(self) -> None:
+        ye = TestYAMLEditable()
+        ye.supported_private_objects = ["foo"]
+        foo1 = ye.vcard.add("X-FOO")
+        foo1.value = "AAA"
+        foo1.group = "1"
+        label1 = ye.vcard.add("X-ABLABEL")
+        label1.value = "yyy"
+        label1.group = "1"
+        foo2 = ye.vcard.add("X-FOO")
+        foo2.value = "BBB"
+        foo2.group = "2"
+        label2 = ye.vcard.add("X-ABLABEL")
+        label2.value = "xxx"
+        label2.group = "2"
+        result = ye._get_private_objects()
+        self.assertEqual(result, {"foo": [{"xxx": "BBB"}, {"yyy": "AAA"}]})