Go around false positive E701 with NameTuple

We get a false positive flake8 throws with pycodestyle 2.3.1 in
travis: https://travis-ci.org/raiden-network/raiden/jobs/414275990

There is an issue in the upstream repo of pycodestyle for this:
PyCQA/pycodestyle#635

[ci integration]

requirements-lint.txt

@@ -1,3 +1,9 @@
+# pycodestyle==2.4.0
+# To avoid [this](https://github.com/PyCQA/pycodestyle/issues/635) bug
+# we need pycodestyle 2.4.0 but unfortunately this does not work with flake8
+# due to https://github.com/PyCQA/pycodestyle/issues/741
+# Once a new version of flake8 is released we can specify the latest pycodestyle
+# version here
 flake8==3.5.0
 flake8-bugbear==18.2.0
 flake8-coding==1.3.0

setup.cfg

@@ -1,5 +1,5 @@
 [flake8]
-ignore = E731, E402, W504, C814
+ignore = E701, E731, E402, W504, C814
 max-line-length = 99
 exclude = raiden/ui/web/node_modules/ tools/ansible/contrib
 # We don't want any 'encoding: ...' headers in source files