How to use the webdriverio/build/utils.checkUnicode function in webdriverio

// However ' DELETE /wd/hub/session/*/actions' is not implmeneted at the very least in uiatomator2
    // and `keys` crashes.
    // thus, do same thing as WDIO except releaseActions

    /**
     * replace key with corresponding unicode character
     */
    if (typeof value === 'string') {
        keySequence = checkUnicode(value);
    } else if (Array.isArray(value)) {
        // `instanceof Array` behaves strange when executed through vm.runInNewContext,
        // it returns false for arrays and `driver.keys()` tests for arrays using `instaceof Array`
        // thus we test using Array.isArray instead
        // https://github.com/felixge/node-sandboxed-module/issues/13#issuecomment-299585213
        for (const charSet of value) {
            keySequence = keySequence.concat(checkUnicode(charSet));
        }
    } else {
        throw new Error('"keys" command requires a string or array of strings as parameter');
    }

    /**
     * JsonWireProtocol action
     */
    if (!this.driver.isW3C) {
        this.driver.sendKeys(keySequence);
        return;
    }

    /**
     * W3C way of handle it key actions
     */

module.exports = function(value) {
    this.helpers.assertArgument(value);

    let keySequence = [];

    // WDIO implmentation of keys command invokes 'releaseActions' for W3C.
    // However ' DELETE /wd/hub/session/*/actions' is not implmeneted at the very least in uiatomator2
    // and `keys` crashes.
    // thus, do same thing as WDIO except releaseActions

    /**
     * replace key with corresponding unicode character
     */
    if (typeof value === 'string') {
        keySequence = checkUnicode(value);
    } else if (Array.isArray(value)) {
        // `instanceof Array` behaves strange when executed through vm.runInNewContext,
        // it returns false for arrays and `driver.keys()` tests for arrays using `instaceof Array`
        // thus we test using Array.isArray instead
        // https://github.com/felixge/node-sandboxed-module/issues/13#issuecomment-299585213
        for (const charSet of value) {
            keySequence = keySequence.concat(checkUnicode(charSet));
        }
    } else {
        throw new Error('"keys" command requires a string or array of strings as parameter');
    }

    /**
     * JsonWireProtocol action
     */
    if (!this.driver.isW3C) {