def _sample(
            self, 
            n: int,
        ) -> np.ndarray:
        """
        Randomly sample ``n`` instances of a decision variable.
        This is an abstract private method governing the behavior of the 
        ``sample`` method.

        Parameters
        ----------
        n : int
            Number of decision variable samples which to draw.

        Returns
        -------
        out : np.ndarray
            An array of shape ``(n,)`` containing sampled decision variables.
        """
        pass

        Randomly sample ``n`` instances of a decision variable.
        This is an abstract private method governing the behavior of the 
        ``sample`` method.

        Parameters
        ----------
        n : int
            Number of decision variable samples which to draw.

        Returns
        -------
        out : np.ndarray
            An array of shape ``(n,)`` containing sampled decision variables.
        
pymoo/core/variable.py