def convert_tokens_to_ids(self, tokens):
        """Converts a sequence of tokens into ids using the vocab."""
        ids = []
        for token in tokens:
            ids.append(self.vocab[token])
        if len(ids) > self.max_len:
            raise ValueError(
                "Token indices sequence length is longer than the specified maximum "
                " sequence length for this BERT model ({} > {}). Running this"
                " sequence through BERT will result in indexing errors".format(
                    len(ids), self.max_len))
        return ids
Converts a sequence of tokens into ids using the vocab.
training/BingBertGlue/pytorch_pretrained_bert/tokenization.py