class NodeBase:
    ...


class ConnectionBase:
    ...


class FlowSceneBase:
    ...


class Serializable:
    'Interface for a serializable class'

    def save(self) -> dict:
        """
        Save

        Returns
        -------
        value : dict
        """
        ...

    def restore(self, state: dict):
        """
        Restore

        Parameters
        ----------
        state : dict
        """
        ...
