Travis provides Python 3.6.1 on Trusty

Author: henryiii

.travis.yml

@@ -46,8 +46,7 @@ matrix:
     env: PYTHON=3.6 CPP=11 GCC=4.8
     addons:
       apt:
-        sources: [deadsnakes]
-        packages: [python3.6-dev python3.6-venv, cmake=2.\*, cmake-data=2.\*]
+        packages: [python3-venv, cmake=2.\*, cmake-data=2.\*]
   - sudo: true
     services: docker
     env: PYTHON=2.7 CPP=14 GCC=6 CMAKE=1