bshi/requests — comment on commit 45b1072caf3883bb71af2507f7edcee5159f620e
File:  line 0
By bshi:

Another possibility is to add

```python
elif isinstance(headers, unicode):
return headers.encode('ascii')
```

Which will handle the common case of a user accidentally using unicode which is reasonable - and will throw a more informative error in the edge case.