High-Frequency DPO

Query intraday minute-bar DPO (Detrended Price Oscillator) for A-share securities via the market data service.DPO removes the trend component to identify cycles. Default: n=20, m=6.line selects output: 'DPO' (oscillator) or 'MADPO' (MA of DPO).codes: comma-separated security codes (e.g. '600000.SH,000001.SZ').interval: minute bar width — 1/3/5/10/15/30/60.starttime/endtime: 'YYYY-MM-DD HH: MM: SS' intraday range.