diff --git a/bob/bio/base/preprocessor/Preprocessor.py b/bob/bio/base/preprocessor/Preprocessor.py
index b8382b08b583af172afc386e8caf343f2e92ef43..48378e79a49ec15f380e999abf7d1fb55de1fe46 100644
--- a/bob/bio/base/preprocessor/Preprocessor.py
+++ b/bob/bio/base/preprocessor/Preprocessor.py
@@ -42,7 +42,7 @@ class Preprocessor (object):
 
     # The call function (i.e. the operator() in C++ terms)
     def __call__(self, data, annotations):
-        """__call__(data, annotations) -> dara
+        """__call__(data, annotations) -> data
 
         This is the call function that you have to overwrite in the derived class.
         The parameters that this function will receive are: