diff --git a/.travis.yml b/.travis.yml
index 0de6f86..d3cf487 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
 group: travis_latest
+dist: xenial  # required for Python >= 3.7 (travis-ci/travis-ci#9069)
 language: python
 cache: pip
 matrix:
@@ -7,19 +8,16 @@ matrix:
   include:
     - python: 3.6
     - python: 3.7
-      dist: xenial  # required for Python >= 3.7 (travis-ci/travis-ci#9069)
     - python: nightly
-      dist: xenial
 install:
-  - pip install -r requirements.txt
-  - pip install flake8
+  - pip install flake8 -r requirements.txt
 before_script:
   # stop the build if there are Python syntax errors or undefined names
-  - flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
+  - flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
   # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
   - flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
 script:
-  - python3 -m unittest tests.all --buffer --verbose
+  - python -m unittest tests.all --buffer --verbose
 notifications:
   on_success: change
   on_failure: change  # `always` will be the setting once code changes slow down