def QA_indicator_BOLL(DataFrame, N=20, P=2):
    '布林线'
    C = DataFrame['close']
    boll = MA(C, N)
    UB = boll + P * STD(C, N)
    LB = boll - P * STD(C, N)
    DICT = {'BOLL': boll, 'UB': UB, 'LB': LB}

    return pd.DataFrame(DICT)
布林线