flake8 2.5.3 is broken: https://gitlab.com/pycqa/flake8/issues/119

setup.py

diff --git a/setup.py b/setup.py
index 82bdf2b..019e10b 100644
--- a/setup.py
+++ b/setup.py
@@ -27,7 +27,7 @@
     packages=find_packages('.', exclude=('tests*', 'testing*')),
     install_requires=[
         # quickfix to prevent pep8 conflicts
-        'flake8',
+        'flake8!=2.5.3',
         'argparse',
         'autopep8>=1.1',
         'pyyaml',