dev_tools/pylint fails with pylint-3 and later
The pylint execution fails on loading the custom 'pylint_copyright_checker' plugin. Related to https://github.com/quantumlib/Cirq/issues/6351
There is no pylint_copyright_checker.py file in this repository, but there
is also no wrong-or-nonexistent-copyright-notice check enabled in dev_tools/.pylintrc.
pylint-3 seems to error on plugins that do not exists, whereas pylint-2 silently ignored them.
It also discovers a plenty of lint issues that were not reported before (perhaps missing --recursive=yes).
This should be re-scoped to syncing with cirq pylint settings.
@dstrain115 - please reopen, there are open TODO items in dev_tools/.pylintrc for rules that need to be fixed and enabled.
@solodov If you want to help with these, we need to enable the pylint tests one-by-one and fix the resulting pylint errors.