Oh is that it? I already have python 2.7 installed.
I can do the path stuff no problem but I probably wouldn't bother. I'd just write batch files in my source code directory to invoke the assembler.
Python is now up to version 3.6 something, this may or may not matter. I'm taking some lessons on stackskills on it now, though my boss came in and told me to start studying on Cold Fusion, for a new client. Learning never ends.