def migrate(self):
        for item in self.get_old_states():
            new_state = self.schema_class.migrate(item)
            old_key = item['id']
            self.backend.purge(old_key)
            if new_state:
                logger.debug("Migrating old state %s.", old_key)
                self.backend.put(new_state)
Temporary method, used to update all expressions to the new format
dataset/ETHPy150Open cloudtools/nymms/nymms/state/State.py/StateManager.migrate