'Create a transfer object.'

def _create_transfer(self, volume_id=None):

    transfer = {'display_name': 'display_name', 'salt': 'salt', 'crypt_hash': 'crypt_hash'}
    if (volume_id is not None):
        transfer['volume_id'] = volume_id
    return db.transfer_create(self.ctxt, transfer)['id']
