macd指标 仅适用于Series
    对于DATAFRAME的应用请使用QA_indicator_macd

def MACD(Series, FAST, SLOW, MID):
    """macd指标 仅适用于Series
    对于DATAFRAME的应用请使用QA_indicator_macd
    """
    EMAFAST = EMA(Series, FAST)
    EMASLOW = EMA(Series, SLOW)
    DIFF = EMAFAST - EMASLOW
    DEA = EMA(DIFF, MID)
    MACD = (DIFF - DEA) * 2
    DICT = {'DIFF': DIFF, 'DEA': DEA, 'MACD': MACD}
    VAR = pd.DataFrame(DICT)
    return VAR