diff --git a/.travis.yml b/.travis.yml
index e14ea764ee845bc8ac4be61bd6979f22a2b69055..dea69f600f90afca9aa136cfd803941c9149911d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,7 @@
 language: node_js
 python:
-  - 8
-  - 9
+  - "8"
+  - "9"
 
 # command to install dependencies
 install: