field.coord('longitude').create_bounds(in_place=True)

I find my self doing

```
bounds=field.coord('longitude').create_bounds()
field.coordinate('longitude').set_bounds(bounds)
```

would it be possible to have an

`field.coord('longitude').create_bounds(in_place=True)`

to do this in a single line?

It's not a huge issue, but just a suggestion!