getSeriesTotals() {
    const w = this.w

    w.globals.seriesTotals = w.globals.series.map((ser, index) => {
      let total = 0

      if (Array.isArray(ser)) {
        for (let j = 0; j < ser.length; j++) {
          total += ser[j]
        }
      } else {
        // for pie/donuts/gauges
        total += ser
      }

      return total
    })
  }
@memberof Core
returns the sum of all values in a series
Eg. w.globals.series = [[32,33,43,12], [2,3,5,1]]
 @return [120, 11]