def to_json(self):
    """Returns the JSON form of this class."""
    return {
        'utterance_wordpieces': [
            wordpiece.to_json() for wordpiece in self.utterance_wordpieces
        ],
        'tables': [table.to_json() for table in self.tables],
        'original_utterance': self.original_utterance
    }
Returns the JSON form of this class.
language/xsp/data_preprocessing/nl_to_sql_example.py