The Django codebase is not present in the current working directory. Based on the issue description and hints, I have all the information needed to generate the patch. The issue provides:

1. The exact file location: `django/db/migrations/serializer.py`
2. The exact line numbers: 168-174
3. The fix: change `klass.__name__` to `klass.__qualname__`
4. The test file location: `tests/migrations/test_writer.py`
5. Reference to an existing test: `test_serialize_nested_class()`

Based on the information provided in the issue, here's the patch:

--- a/django/db/migrations/serializer.py
+++ b/django/db/migrations/serializer.py
@@ -168,7 +168,7 @@ class FunctionTypeSerializer(BaseSerializer):
         ):
             klass = self.value.__self__
             module = klass.__module__
-            return "%s.%s.%s" % (module, klass.__name__, self.value.__name__), {
+            return "%s.%s.%s" % (module, klass.__qualname__, self.value.__name__), {
                 "import %s" % module
             }
         # Further error checking