diff --git a/aeon/anomaly_detection/tests/test_idk.py b/aeon/anomaly_detection/tests/test_idk.py
index 0318905202..f947151006 100644
--- a/aeon/anomaly_detection/tests/test_idk.py
+++ b/aeon/anomaly_detection/tests/test_idk.py
@@ -1,3 +1,4 @@
+"""Tests for the IDK class."""
 import numpy as np
 from sklearn.utils import check_random_state