real time uv scaler

hello scriptspotters!

im learning scripting by bringing down my own needs as archviz artist into scripting language. so I'm creating tools to ease up everything bla bla bla

I have come to a scenario which outruns my very limited skills in scripting languages:

I want to create a tool which scales uvs through a slider in realtime without going through uv ediot in unwrap uv modifier.

here is my tryout to get it done but clearly im missing something huge

$.modifiers[#unwrap_uvw].unwrap2.ScaleSelectedCenter uvsize.value 0 --uvsize being name of my slider

can you guys help me? thanks