If you’re looking around the source for Django, and you’re wondering why arguments that might be named ‘class’ are named ‘klass’ instead of ‘cls’ or ‘class_’ per PEP 8 guidelines (e.g. here), you might be interested to know that the recommendation against ‘klass’ didn’t fully appear in PEP 8 until December, 2005. Prior to that, its use was discouraged, but the major recommendation was consistency.