Convert to JSON.

        Returns
        -------
        `dict`
            JSON data.

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

        Returns
        -------
        `dict`
            JSON data.
        """
        data = super().save()
        data['state_sizes'] = self.state_sizes
        data['reset_on_sentence_end'] = self.reset_on_sentence_end
        return data