def _blockdevicevolume_from_dataset_id(dataset_id, size, attached_to=None):
 return BlockDeviceVolume(size=size, attached_to=attached_to, dataset_id=dataset_id, blockdevice_id=u'block-{0}'.format(dataset_id))

def _blockdevicevolume_from_dataset_id ( dataset_id , size , attached_to = None ) : return BlockDeviceVolume ( size = size , attached_to = attached_to , dataset_id = dataset_id , blockdevice_id = u'block-{0}' . format ( dataset_id ) )
create a new blockdevicevolume with a blockdevice_id derived from the given dataset_id .