CCATP #630 for March 14, 2020, and I'm your host, Allison Sheridan. This week our guest is Bart Busschots with PBS 92 of X in which he walks us through his solution to the assignment from PBS 89 to create a grid of currency conversions.

He doesn't go through his code line by line, but rather gives us the big picture of his process. Most of the time he spent on the solution was actually in refactoring his code because he decided to preload the data rather than fetching it repeatedly on-demand. I loved it when he referred to his original work as "Organically-grown Weasley-kind of code".

He also explains how he used both coercion and assertion to do his error handling and why. Eventually he got to start working on the grid and he walks us through how he cracked that problem. It was great fun as always and we have a new, six-week challenge to build a world clock.

You can find his full tutorial shownotes and download his solution at [pbs.bartificer.net/pbs92](https://pbs.bartificer.net/pbs92)