def _select_target_train_samples(self, x_train: np.ndarray, y_train: np.ndarray) -> tuple[np.ndarray, np.ndarray]:
        """
        Used for selecting train samples from target class
        :param x_train: clean training data
        :param y_train: labels fo clean training data
        :return x_train_target_samples, y_train_target_samples:
        samples and labels selected from target class in train data
        """
        x_train_samples = np.copy(x_train)
        index_target = np.where(y_train.argmax(axis=1) == self.class_target)[0]
        x_train_target_samples = x_train_samples[index_target]
        y_train_target_samples = y_train[index_target]
        return x_train_target_samples, y_train_target_samples

        Used for selecting train samples from target class
        :param x_train: clean training data
        :param y_train: labels fo clean training data
        :return x_train_target_samples, y_train_target_samples:
        samples and labels selected from target class in train data
        
art/attacks/poisoning/sleeper_agent_attack.py