Calculate NIR (No information rate).

    :param P: condition positive
    :type P : dict
    :param POP: population
    :type POP : int
    :return: NIR as float

def NIR_calc(P, POP):
    """
    Calculate NIR (No information rate).

    :param P: condition positive
    :type P : dict
    :param POP: population
    :type POP : int
    :return: NIR as float
    """
    try:
        max_P = max(list(P.values()))
        length = POP
        return max_P / length
    except Exception:
        return "None"