DeepL APScript in Google Sheet not working

Question

I'm trying to use a deepL API function in Google Spreadsheet to translate some JP texts to EN.

For the script, I copied and pasted from this raw Github repository with custom value replaced (API key).

However, when I saved the script and tried the function (=deepL(cell, target_lan, source_lan)), this error showed up.

ReferenceError: httpRequestWithRetries_ is not defined (line 84).

And here is the code I used. Could anyone be able to help with this please?

/**
 * Translates from one language to another using the DeepL Translation API.
 *
 * Note that you need to set your DeepL auth key by calling DeepLAuthKey() before use.
 *
 * @param {"Hello"} input The text to translate.
 * @param {"en"} sourceLang Optional. The language code of the source language.
 *   Use "auto" to auto-detect the language.
 * @param {"es"} targetLang Optional. The language code of the target language.
 *   If unspecified, defaults to your system language.
 * @param {"def3a26b-3e84-..."} glossaryId Optional. The ID of a glossary to use
 *   for the translation.
 * @param {cell range} options Optional. Range of additional options to send with API translation
 *   request. May also be specified inline e.g. '{"tag_handling", "xml"; "ignore_tags", "ignore"}'
 * @return Translated text.
 * @customfunction
 */


function DeepLTranslate(input,
                        sourceLang,
                        targetLang,
                        glossaryId,
                        options
) {
    if (input === undefined) {
        throw new Error("input field is undefined, please specify the text to translate.");
    } else if (typeof input === "number") {
        input = input.toString();
    } else if (typeof input !== "string") {
        throw new Error("input text must be a string.");
    }
    // Check the current cell to detect recalculations due to reopening the sheet
    const cell = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet().getCurrentCell();

    if (disableTranslations) {
        Logger.log("disableTranslations is active, skipping DeepL translation request");
        return cell.getDisplayValue();
    }

    if (activateAutoDetect &&
            cell.getDisplayValue() !== "" &&
            cell.getDisplayValue() !== "Loading...") {
        Logger.log("Detected cell-recalculation, skipping DeepL translation request");
        return cell.getDisplayValue();
    }

    if (!targetLang) targetLang = selectDefaultTargetLang_();
    let formData = {
        'target_lang': targetLang,
        'text': input
    };
    if (sourceLang && sourceLang !== 'auto') {
        formData['source_lang'] = sourceLang;
    }
    if (glossaryId) {
        formData['glossary_id'] = glossaryId;
    }
    if (options) {
        if (!Array.isArray(options) ||
            !Object.values(options).every(function(value) {
                return Array.isArray(value) && value.length === 2;
            })) {
            throw new Error("options must be a range with two columns, or have the form '{\"opt1\", \"val1\"; \"opt2\", \"val2\"}'");
        }

        for (let i = 0; i < options.length; i++) {
            const items = options[i];
            const key = items[0];
            const value = items[1];
            formData[key] = value;
        }
    }

    const response = httpRequestWithRetries_('post', '/v2/translate', formData, input.length);
    checkResponse_(response);
    const responseObject = JSON.parse(response.getContentText());
    return responseObject.translations[0].text;
}