diff --git a/openmc/cross.py b/openmc/cross.py
index b91344671..435557ede 100644
--- a/openmc/cross.py
+++ b/openmc/cross.py
@@ -298,6 +298,7 @@ class CrossFilter(object):
         string += '{0: <16}{1}{2}\n'.format('\tType', '=\t', filter_type)
         string += '{0: <16}{1}{2}\n'.format('\tBins', '=\t', filter_bins)
         return string
+
     def __deepcopy__(self, memo):
         existing = memo.get(id(self))
 
@@ -461,4 +462,4 @@ class CrossFilter(object):
             right_df = right_df.astype(str)
             df = '(' + left_df + ' ' + self.binary_op + ' ' + right_df + ')'
 
-        return df
\ No newline at end of file
+        return df