Fixed #30232 -- Corrected expected format in invalid DurationField error message.

django/db/models/fields/__init__.py

@@ -1587,7 +1587,7 @@ class DurationField(Field):
     empty_strings_allowed = False
     default_error_messages = {
         'invalid': _("'%(value)s' value has an invalid format. It must be in "
-                     "[DD] [HH:[MM:]]ss[.uuuuuu] format.")
+                     "[DD] [[HH:]MM:]ss[.uuuuuu] format.")
     }
     description = _("Duration")
 

tests/model_fields/test_durationfield.py

@@ -75,7 +75,7 @@ class TestValidation(SimpleTestCase):
         self.assertEqual(
             cm.exception.message % cm.exception.params,
             "'not a datetime' value has an invalid format. "
-            "It must be in [DD] [HH:[MM:]]ss[.uuuuuu] format."
+            "It must be in [DD] [[HH:]MM:]ss[.uuuuuu] format."
         )