Similar to DEBUG but at ERROR level with exc_info set.

        https://github.com/python/cpython/blob/2.7/Lib/logging/__init__.py#L1472

def exception(self, msg=None, *args, **kwargs):
        """Similar to DEBUG but at ERROR level with exc_info set.

        https://github.com/python/cpython/blob/2.7/Lib/logging/__init__.py#L1472
        """
        kwargs['exc_info'] = 1
        return self._log(logging.ERROR, msg, args, kwargs)