diff --git a/python/paddle/fluid/average.py b/python/paddle/fluid/average.py
index 42cd3b36420ef5a17a9a7d981978ba8869809936..40a734af311e2037c1816dce97db123ebedd2f4f 100644
--- a/python/paddle/fluid/average.py
+++ b/python/paddle/fluid/average.py
@@ -48,6 +48,7 @@ class WeightedAverage(object):
 
     Examples:
         .. code-block:: python
+
             avg = fluid.average.WeightedAverage()
             avg.add(value=2.0, weight=1)
             avg.add(value=4.0, weight=2)