def save(self):
        """Convert to JSON.

        Returns
        -------
        `dict`
            JSON data.
        """
        data = super().save()
        data['block_size'] = list(self.block_size)
        data['block_sentences'] = self.block_sentences
        data['traverse_image'] = self.traverse_image.save()
        data['traverse_block'] = self.traverse_block.save()
        return data