_call(tokens) {
        tokens = this.encode(tokens);
        if (this.fuse_unk) {
            // Fuse unknown tokens
            tokens = fuse_unk(tokens, this.tokens_to_ids, this.unk_token_id);
        }
        return tokens;
    }
Internal function to call the TokenizerModel instance.
@param {string[]} tokens The tokens to encode.
@returns {string[]} The encoded tokens.