class AddPath:
    def __init__(self, posix_path):
        self.path = str(posix_path)
    def __enter__(self):
        sys.path.insert(0, self.path)
    def __exit__(self, exc_type, exc_value, traceback):
        try:
            sys.path.remove(self.path)
        except ValueError:
            pass
with AddPath(Path(os.getcwd()).parent / 'pa_core'):
    pa_core = __import__('pa_core')