Try to convince TravisCI to run tests on Python 3.7.
sudo: false
+dist: xenial
language: python
python:
- 2.7
- 3.4
- 3.5
-- &latest_py3 3.6
-
-matrix:
- include:
- - python: "3.7"
- dist: xenial
- sudo: true
+- 3.6
+- &latest_py3 3.7
env: TOXENV=python
