diff --git a/.travis.yml b/.travis.yml
index ca9f2762261e2d452f2c6a93e8e1ab793e7155bc..8d725fb17fdfbd7111a9491d7172c997834269b3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,7 +16,7 @@ addons:
       - python2.7-dev
       - golang
 before_install:
-  -  pip install -U virtualenv pre-commit pip
+  -  sudo pip install -U virtualenv pre-commit pip
   -  GOPATH=/tmp/go go get -u github.com/wangkuiyi/ipynb/markdown-to-ipynb
 script:
   -  PATH=/tmp/go/bin:$PATH .travis/precommit.sh
diff --git a/01.fit_a_line/train.py b/01.fit_a_line/train.py
index dba53181b453350efcfca80b31cb288e91076e93..3629523cc802558a01613b4bce6de76685c7ac52 100644
--- a/01.fit_a_line/train.py
+++ b/01.fit_a_line/train.py
@@ -10,7 +10,7 @@ def main():
     x = paddle.layer.data(name='x', type=paddle.data_type.dense_vector(13))
     y_predict = paddle.layer.fc(input=x, size=1, act=paddle.activation.Linear())
     y = paddle.layer.data(name='y', type=paddle.data_type.dense_vector(1))
-    cost = paddle.layer.mse_cost(input=y_predict, label=y)
+    cost = paddle.layer.square_error_cost(input=y_predict, label=y)
 
     # create parameters
     parameters = paddle.parameters.create(cost)