diff --git a/src/image_prediction/pipeline.py b/src/image_prediction/pipeline.py
index 8219a9d..8bf0ff0 100644
--- a/src/image_prediction/pipeline.py
+++ b/src/image_prediction/pipeline.py
@@ -79,6 +79,12 @@ class Pipeline:
 def filter_duplicates(metadata: Iterable[dict[str, Any]]) -> Iterable[dict[str, Any]]:
     """Filter out duplicate images from the `position` (image coordinates), `page` and `representation` (perceptual hash).
     See RED-10765 (RM-241): Removed redactions reappear for why this is necessary.
+
+    Args:
+        metadata: Iterable of image metadata dicts.
+
+    Returns:
+        Iterable of image metadata dicts with duplicates removed.
     """
     seen = set()
     for item in metadata: