Fix comments and unittest for market.py and style

Trying to make the right commit to  the develop branch.
There is no need to unit-test lazy logging. If there is an error with the formatting string, the [logging checker](http://docs.pylint.org/features.html#logging-checker) of `pylint` will flag it, as we have all relevant error flags (E1200, E1201, E1205, E1206) flags enabled.

Please remove the file from the PR.