@weblab_api.route_web('/language/')
def language():
    accept_language = request.headers.get('Accept-Language')
    if accept_language is None:
        contents = 'var acceptLanguageHeader = null;'
    else:
        contents = accept_language % 'var acceptLanguageHeader = "%s";'
    
    response = make_response(contents)
    response.content_type = 'text/javascript';
    return response
dataset/ETHPy150Open weblabdeusto/weblabdeusto/server/src/weblab/core/web/language.py/language/swapped operands of `%`