speed up apply calculation 
Hi, I have a huge database with multi index ((8832, 14384)) from which I calculate some statistics with code like that : 

```python
(df
 .apply([
     lambda x: ...,  
     lambda x: ...,
     lambda x: ...,
     lambda x: ...,
     lambda x: ...,

     lambda x: ...,
     lambda x: ...,
     lambda x: ...,
     lambda x: ...,
     lambda x: ...,
     lambda x: ...,

     lambda x: ...,
     lambda x: ...,
     lambda x: ...,
     lambda x: ...,

     lambda x: ...,
     lambda x: ...,

     lambda x: ...,
     lambda x: ...,
 ], axis=1)
)
```
My problem is that it took **more than 5 min** to do the calculation (!!!!). 
Is there a way to do it better ? Multiprocessing but don't know how to structure it ? 

Thx 