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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def micro_calc(TP, item):
 """ Calculate PPV_Micro and TPR_Micro. :param TP: true positive :type TP:dict :param item: FN or FP :type item : dict :return: PPV_Micro or TPR_Micro as float """

    try:
        TP_sum = sum(TP.values())
        item_sum = sum(item.values())
        return TP_sum / (TP_sum + item_sum)
    except Exception:
        return "None"