What value does this add? 
The exc_info contains all (and some more) that you need. See
```python
>>> try:
...   d['x']
... except KeyError, x:
...   logging.error(x, exc_info=True)
...
ERROR:root:'x'
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
KeyError: 'x'
```