diff --git a/pympipool/shared_functions/external_interfaces.py b/pympipool/shared_functions/external_interfaces.py
index 9f1d819d..ade7994f 100644
--- a/pympipool/shared_functions/external_interfaces.py
+++ b/pympipool/shared_functions/external_interfaces.py
@@ -10,6 +10,13 @@
 
 
 def cancel_items_in_queue(que):
+    """
+    Cancel items which are still waiting in the queue. If the executor is busy tasks remain in the queue, so the future
+    objects have to be cancelled when the executor shuts down.
+
+    Args:
+        que (queue.Queue): Queue with task objects which should be executed
+    """
     while True:
         try:
             item = que.get_nowait()