cci(src, len, _id) {
        // TODO: Not exactly precise, but pretty damn close
        let id = this._tsid(_id, `cci(${len})`)
        let ma = this.sma(src, len, id)
        let dev = this.dev(src, len, id)
        let cci = (src[0] - ma[0]) / (0.015 * dev[0])
        return this.ts(cci, id, src.__tf__)
    }
Commodity Channel Index
@param {TS} src - Input
@param {number} len - Length
@return {TS} - New time-series