'Prepare a snapshot for direct reference from glance.
The implementation of this method is optional and therefore is
not an abstractmethod.
:raises: exception.ImageUnacceptable if it cannot be
referenced directly in the specified image format
:returns: URL to be given to glance'

def direct_snapshot(self, context, snapshot_name, image_format, image_id, base_image_id):

    raise NotImplementedError(_('direct_snapshot()    is    not    implemented'))
