diff --git a/order/msd.py b/order/msd.py
index 350772b..d4baa51 100644
--- a/order/msd.py
+++ b/order/msd.py
@@ -49,7 +49,7 @@ def mean_square_displacement(self, max_t = 1000, freq = 1):
             bar.next()
         bar.finish()
 
-   def out_put(self, taskname='MSD'):
+    def out_put(self, taskname='MSD'):
         """output raw data of msd"""
         raw_data = self.fprefix + '_' + taskname + '_raw.dat'
         with open(raw_data, 'w') as f: