docs: add docstring

robotoff/insights/importer.py

@@ -1978,6 +1978,15 @@ def get_product_predictions(
     server_type: ServerType,
     prediction_types: Optional[list[str]] = None,
 ) -> Iterator[dict]:
+    """Fetch from DB predictions with barcode in `barcodes`.
+
+    :param barcodes: the barcodes we want to fetch
+        predictions for.
+    :param server_type: filter by server type (project)
+    :param prediction_types: filter by prediction types, defaults to None
+        (fetch all types)
+    :yield: predictions as dict
+    """
     where_clauses = [
         PredictionModel.barcode.in_(barcodes),
         PredictionModel.server_type == server_type.name,