哪位大神可以推荐一个多空切换的趋势指标，万分拜谢！

indicator(title='[SHK] Schaff Trend Cycle (STC)', shorttitle='STC', overlay=false)
EEEEEE = input(12, 'Length')
BBBB = input(26, 'FastLength')
BBBBB = input(50, 'SlowLength')

AAAA(BBB, BBBB, BBBBB) =>
    fastMA = ta.ema(BBB, BBBB)
    slowMA = ta.ema(BBB, BBBBB)
    AAAA = fastMA - slowMA
    AAAA