diff --git a/bob/pad/face/preprocessor/PPGSecure.py b/bob/pad/face/preprocessor/PPGSecure.py
index 847d08af069b1224cd99312885a7c2f436e8acac..2a09fa761a64187d4170aedd86d68c31817b0930 100644
--- a/bob/pad/face/preprocessor/PPGSecure.py
+++ b/bob/pad/face/preprocessor/PPGSecure.py
@@ -176,8 +176,8 @@ class PPGSecure(Preprocessor):
 
     Returns
     -------
-      masks: :py:obj:`list` of numpy.ndarray
-        A list containing the different mask as a boolean array
+    masks: :py:obj:`list` of numpy.ndarray
+      A list containing the different mask as a boolean array
         
     """
     masks = []