The general advice to people using Kanban/Agile Project boards of various kinds is this:
Stop Starting -- Start Finishing

etc.
There's a lot of this advice. Some of it is helpful.
Many tools have various dashboards and metrics computations.
However.
The basic velocity calculations -- starts v. finishes -- is pretty straight-forward. The rules to classify a Trello action as "start" or "finish" are actually nice examples of simple functions or lambdas. Which also means that the basic pipeline required to gather the data can be written as a lazy, functional process.
Which leads to writing a Literate Programming version of a small program that gathers data from a Trello board.
It's a kind of deep-dive into some aspects of Python functional-style programming. It's also a dive into Literate Programming via a longish example. And it has a fair number of type hints. It's not perfectly clean from MyPy-'s analysis. So there's some more to do on that front.