Testing Python Linters

Based on recommendations via comments on an earlier post, my March column is a survey of a few different “lint” programs for Python (it looks like I’ll stick to PyChecker, pylint, and PyFlakes for now). I need some sample code to run through all 3 programs so I can compare the output reports. I have a few ideas for common “mistakes” to include, but I’m looking for other suggestions.

So, what kinds of things are these tools good at finding, and where do they need more work? Are there any false-positives I should make sure to include?