How to create .pk file?

Hi! Thank you for publishing such great work！
I am a little bit confused about how to generate the data file.
It appears that the code here in train.py 
```python
self.vid_list = data['vid_list']
self.vid_lookup = data['vid_lookup']
self.uid_list = data['uid_list']
self.data_neural = data['data_neural']
```
requires some fileds.
Could you please explain what that means?