How to use the parcel-bundler/src/Logger.warn function in parcel-bundler

getTranscryptRunInfo() {
        if (this.options['watch']) {
            if (fs.existsSync(this.runInfoPath)) {
                try {
                    return JSON.parse(fs.readFileSync(this.runInfoPath, 'utf8'));
                }catch (err) {
                    logger.warn(`${LOG_PREFIX} Unable to read transcrypt dependencies for watch mode: ${err}`);
                }
            }
        }
        return {};
    }