diff --git a/mufs/Selection.py b/mufs/Selection.py
index eb328e6..9eb6ed9 100755
--- a/mufs/Selection.py
+++ b/mufs/Selection.py
@@ -128,7 +128,7 @@ class MUFS:
         k = len(features)
         for pair in list(combinations(features, 2)):
             rff += self._compute_su_features(*pair)
-        return rcf / sqrt(k + (k ** 2 - k) * rff)
+        return rcf / sqrt(k + (k**2 - k) * rff)
 
     def cfs(self, X, y):
         """Correlation-based Feature Selection