from abc import ABC, abstractmethod
from typing import Any, Callable


class Communicator(ABC):
    """pub/sub model via specific protocol."""

    @abstractmethod
    def publish(self, topic: str, payload: Any, retain: bool = False) -> None:
        """Send data via specific protocol."""
        pass

    @abstractmethod
    def subscribe(self, receiver: Callable) -> None:
        """Pass receiver so communicators can pass commands."""
        pass

    @abstractmethod
    def stop(self) -> None:
        """Stop the communicator."""
        pass