src/transformers/models/ernie_m/tokenization_ernie_m.py/ErnieMTokenizer/load_vocab
class ErnieMTokenizer:    def load_vocab(self, filepath):
        token_to_idx = {}
        with io.open(filepath, "r", encoding="utf-8") as f:
            for index, line in enumerate(f):
                token = line.rstrip("\n")
                token_to_idx[token] = int(index)

        return token_to_idx