diff --git a/dmff/mbar.py b/dmff/mbar.py
index d615ad34e..4e55e7957 100644
--- a/dmff/mbar.py
+++ b/dmff/mbar.py
@@ -4,7 +4,7 @@
 except ImportError:
     import warnings
     warnings.warn("MDTraj not installed. MBAREstimator is not available.")
-##
+
 try:
     from pymbar import MBAR
 except ImportError: