Hi there! Recently I submitted such piece of code to one of my projects: if 'text' in d.get('a'): # do something Obviously that was expected to be something like: if 'text' in d.get('a', ''): # do something because .get() might return None, and checking if something is contained in None gives you TypeError. Maybe it was too late, I was trying to finish this piece of code asap and I expected flakes8 to detect this for me, so when PR became green I merged it. When I realized this piece of code is buggy it was too late :) As I don't want to repeat this mistake I decided to take measures. As I was using flakes8 at the moment and it didn't notice this bug - I thought "Hm, maybe I should use some better tool, maybe pyflakes is too simple to catch that". So I tried pylint and prospector. They do almost everything, I believe both tools can bring you coffee in the bed. But they cannot detect such a simple error. No success. And that makes me really unhappy. Do you guys know any Python code analyzer which is able to catch such problem? Is there a chance this can be implemented in pyflakes? If so - should I create bug on https://bugs.launchpad.net/pyflakes/+filebug? -- Best regards, Alexander Chekunkov