async getNumberId(number) {
        if (!number.endsWith('@c.us')) {
            number += '@c.us';
        }

        return await this.pupPage.evaluate(async number => {
            const wid = window.Store.WidFactory.createWid(number);
            const result = await window.Store.QueryExist(wid);
            if (!result || result.wid === undefined) return null;
            return result.wid;
        }, number);
    }
Get the registered WhatsApp ID for a number. 
Will return null if the number is not registered on WhatsApp.
@param {string} number Number or ID ("@c.us" will be automatically appended if not specified)
@returns {Promise<Object|null>}