AAA99: collision when marking this line as NEW_CODE, was already OLD_CODE

This is an error code that is raised when Flake8 tries to mark a single line as occupied by two different types of block. It should never happen. The values for NEW_CODE and OLD_CODE are from the list of Line markers.


Please open a new issue containing the output for the failing test as generated by the Command line tool.

You could hack around with your test to see if you can get it to work while waiting for someone to reply to your issue. If you’re able to adjust the test to get it to work, that updated test would also be helpful for debugging.