"""English implementation note."""
from __future__ import annotations
from typing import Protocol, runtime_checkable
import numpy as np

@runtime_checkable
class BackboneProtocol(Protocol):
    """English implementation note."""
    W: np.ndarray

    @property
    def cfg(self):
        """English implementation note."""
        ...

    def encode(self, X: np.ndarray) -> np.ndarray:
        """English implementation note."""
        ...