'Attaches volume to node.
:param node: Node to attach volume to.
:type node: :class:`.Node`
:param volume: Volume to attach.
:type volume: :class:`.StorageVolume`
:param device: Where the device is exposed, e.g. \'/dev/sdb\'
:type device: ``str``
:rytpe: ``bool``'

def attach_volume(self, node, volume, device=None):

    attr = {'type': 'attach', 'droplet_id': node.id, 'volume_id': volume.id, 'region': volume.extra['region_slug']}
    res = self.connection.request('/v2/volumes/actions', data=json.dumps(attr), method='POST')
    return (res.status == httplib.ACCEPTED)
