'Perform umount operation on the temporary dir
:rtype: None'

def close(self):

    if os.path.ismount(self.mnt_dir):
        utils.run(('fuser    -k    %s' % self.mnt_dir), ignore_status=True)
        utils.run(('umount    %s' % self.mnt_dir))
    shutil.rmtree(self.mnt_dir)
