something wrong in example

![image](https://user-images.githubusercontent.com/42565075/54999939-5789f780-500c-11e9-958f-1c7b0b92a257.png)

the segmentation is wrong。。
Do you have the latest `pytorch-pretrained-bert` ?
```python
import pytorch_pretrained_bert
pytorch_pretrained_bert.__version__
```<|||||>Thank you so much!!!!!!!<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
