divideByOnlyMetric = (divisor, metricNames) =>
  mathValuesSelective((v) => v / divisor, (i) => metricNames.includes(i.metric))
Perform a division of values by a constant for the given metrics

@param {number} divisor the constant that will be the divisor
@param {metricNames} array the list of metric names to transform
@return {function} a transform function