code: func emptyChartEntries(t time.Time, limit int) ChartEntries {
  	ce := make(ChartEntries, limit)
  	for i := 0; i < limit; i++ {
  		ce[i] = new(ChartEntry)
  	}
  	return ce
  }
docs: // emptyChartEntries returns a ChartEntry array containing limit number of empty samples.