def clean_stock_selection(uncleaned_stocks):
    """
    Function to perform some cleaning before using urllib.requests and finance.yahoo.com to obtain all the stockinfo.

    Inputs:
        - uncleaned_stocks(pd.DataFrame): pd.DataFrame containing the stocks (name, wkn, exchange, ticker, ISIN, ...)
    Returns:
        - pd.DataFrame cleaned s.t. every stock has an industry.

    """
    return uncleaned_stocks[uncleaned_stocks.industry != "not_found"]