Fix comments and unittest for market.py and style

Trying to make the right commit to  the develop branch.
Bullet point style:
* We *shouldn't* have lazy logging right now; there are bugs in our logging system and we shouldn't silence them. But since you have already done that for us, I 'll accept it.
* We *will* have lazy logging once we are out of betas and the logging system has matured.
* There will *never* be a need to test the implementation of lazy logging. Python developpers have already done that [already](https://github.com/python-git/python/blob/master/Lib/test/test_logging.py).

I hope I made myself clear. If you believe I am in error, please wait for a professional developer.