def status_calc(stock, sp500, outperformance=10):
    """A simple function to classify whether a stock outperformed the S&P500
    :param stock: stock price
    :param sp500: S&P500 price
    :param outperformance: stock is classified 1 if stock price > S&P500 price + outperformance
    :return: true/false
    """
    if outperformance < 0:
        raise ValueError("outperformance must be positive")
    return stock - sp500 >= outperformance