diff --git a/nltools/data/brain_data.py b/nltools/data/brain_data.py
index aacb79ae..8487bedc 100644
--- a/nltools/data/brain_data.py
+++ b/nltools/data/brain_data.py
@@ -1273,9 +1273,9 @@ def predict(self, algorithm=None, cv_dict=None, plot=True, verbose=True, **kwarg
                             self.data[test]
                         )
                     else:
-                        output["dist_from_hyperplane_xval"][test] = (
-                            predictor_cv.decision_function(self.data[test])
-                        )
+                        output["dist_from_hyperplane_xval"][
+                            test
+                        ] = predictor_cv.decision_function(self.data[test])
                         if (
                             predictor_settings["algorithm"] == "svm"
                             and predictor_cv.probability