It looks like the graphical part is optional. You could just have one big node that was a Python program. Hopefully that means you could use the arrows and boxe

It looks like the graphical part is optional. You could just have one big node that was a Python program. Hopefully that means you could use the arrows and boxes only where they are natural. They'll at least be natural to impose at the top level of your program. They might also be useful at lower levels, if it's possible to make a functional abstraction out of a signal diagram. Diffs will still be a problem though. I wouldn't touch this stuff with a ten foot pole.