High-Frequency Bollinger Bands

Query intraday minute-bar BOLL (Bollinger Bands) for A-share securities via the market data service.MID = MA(close, N); UPPER = MID + k * std; LOWER = MID - k * std. Default: N=26, k=2.line selects the output band: 'MID' (middle), 'UPPER' (upper), or 'LOWER' (lower).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.