make sys.path.append auto detect

[dwiga]

Hi,
I facing a problem coding in jython.
but, what I want to ask is about python.
I have to write this code on every file I've create

sys.path.append("D:\AvosLab\digital_scale\python")

but, the problem is my friends and I using git to build that app, so between my friends and I have different path of work.
so, how to make a code wich autodetect without changing the path every pulling project from git.

thank you in advance...