Learning about my own code assumptions

I don't think it's controversial at all to say that "our analysis code, any analysis code, is full of assumptions". We all know on a fundamental level that when we model something in code, we're taking a very specific path in a wide open field of possibility. But it wasn't until I was trying to write example code for an analysis that it really really hit home for me just how many assumptions and decisions were loaded everywhere.

As an example, here's the simple "count sessions" example code for the logs class. It reads through a CSV log that follows a very specific format, and by leaning heavily on the fact that the log entries are sorted in chronological order, it can calculate sessions in a very memory efficient way.