Fix for Python 3.7 on Travis

jmcclell · jmcclell · commit 608bddd7d080 · 2018-10-13T07:38:02.000-04:00
travis-ci/travis-ci#9069 (comment)
diff --git a/.travis.yml b/.travis.yml
@@ -1,4 +1,6 @@
 language: python
+sudo: required
+dist: xenial
 python:
   - "2.7"
 # - "3.2"  Has been dropped by many dependencies
