Hi On circle ci when I run flake I get the following error, but when I run it locally everything runs smoothly and I am uncapable of reprducing it, but somehow on circle ci fails. Does anyone have an idea what it could be the issue, see Error below Thanks in advance for any hints and your time. Best, Farncesc The error: flake8 --ignore=E712 background_tasks Traceback (most recent call last): File "/home/ubuntu/virtualenvs/venv-3.5.1/bin/flake8", line 5, in <module> main() File "/home/ubuntu/virtualenvs/venv-3.5.1/lib/python3.5/site-packages/flake8/run.py", line 48, in main options, args = pep8.process_options() File "/home/ubuntu/virtualenvs/venv-3.5.1/lib/python3.5/site-packages/flake8/pep8.py", line 1343, in process_options options.physical_checks = find_checks('physical_line') File "/home/ubuntu/virtualenvs/venv-3.5.1/lib/python3.5/site-packages/flake8/pep8.py", line 812, in find_checks for name, function in globals().items(): RuntimeError: dictionary changed size during iteration