def static(filename):
    """Provides the 'static' function that also appends the file's timestamp to the URL, usable in a template."""
    timestamp = os.path.getmtime(os.path.join(app.static_folder, filename))
    return (app.static_url_path, filename, timestamp) % "%s/%s?%s"

# Flask application
dataset/ETHPy150Open joeyespo/flask-scaffold/[appname].py/static/swapped operands of `%`