I want to add hours to a `datetime` and use: 

```
date = date_object + datetime.timedelta(hours=6)

```

Now I want to add a time:  

`time='-7:00'` (string) plus 4 hours.

I tried `hours=time+4` but this doesn't work. I think I have to `int` the string like `int(time)` but this doesn't work either.