Extract package to a temporary folder.

        Return:
            pathlib.Path: Temp dir with package contents.

def _extract(filename):
        """Extract package to a temporary folder.

        Return:
            pathlib.Path: Temp dir with package contents.

        """
        random_string = '{:0d}'.format(randint(0, 10**6))
        tmp = '/tmp/kytos-napp-' + Path(filename).stem + '-' + random_string
        os.mkdir(tmp)
        with tarfile.open(filename, 'r:xz') as tar:
            tar.extractall(tmp)
        return Path(tmp)