@property<EOL><INDENT>def src_vocab(self):<DEDENT>
if self._src_vocab is None:<EOL><INDENT>src_vocab_file_name, src_vocab_hash =self._data_file[self._pair_key]['<STR_LIT>' + '<STR_LIT:_>' + self._src_lang]<EOL>[src_vocab_path] = self._fetch_data_path([(src_vocab_file_name, src_vocab_hash)])<EOL>with io.open(src_vocab_path, '<STR_LIT:r>', encoding='<STR_LIT:utf-8>') as in_file:<EOL><INDENT>self._src_vocab = Vocab.from_json(in_file.read())<EOL><DEDENT><DEDENT>return self._src_vocab<EOL>
Source Vocabulary of the Dataset.

        Returns
        -------
        src_vocab : Vocab
            Source vocabulary.