Try sudo

.travis.yml

@@ -5,6 +5,8 @@ dist: trusty
 env:
   global:
     - DJANGO_SETTINGS_MODULE="tests.app.settings"
+  matrix:
+    - TOX_ENV=flake8,isort
 
 matrix:
   include:
@@ -18,10 +20,12 @@ matrix:
       python: 3.6
     - env: TOXENV=py37-dj20-wt24
       python: 3.7
+      sudo: true
       dist: xenial
     - env: TOXENV=py37-dj21-wt24
       python: 3.7
       dist: xenial
+      sudo: true
     - env: TOXENV=py35-dj20-wt25
       python: 3.5
     - env: TOXENV=py35-dj21-wt25
@@ -33,12 +37,15 @@ matrix:
     - env: TOXENV=py37-dj20-wt25
       python: 3.7
       dist: xenial
+      sudo: true
     - env: TOXENV=py37-dj21-wt25
       python: 3.7
       dist: xenial
+      sudo: true
     - env: TOXENV=py37-dj22-wt25
       python: 3.7
       dist: xenial
+      sudo: true
     - env: TOX_ENV='flake8,isort'
       python: 3.5