Converting Relative Path to Absolute Path in Python

#!/usr/bin/env python

def get_absolute_path(path):
    files = path.split("/")
    l = []
    for f in files:
        if f == "..":
            l.pop()
        else:
            l.append(f)
    return "/".join(l)

if __name__ == "__main__":
    assert "/windows/temp/" == get_absolute_path("/windows/abs/../temp/new/../")
    assert "windows/temp/" == get_absolute_path("windows/abs/../temp/new/../")
    assert "/windows/temp" == get_absolute_path("/windows/abs/../temp/new/..")