code: func (m *Metric) stats(name string) (*cloudwatch.GetMetricStatisticsOutput, error) {
  	return m.Service.GetMetricStatistics(&cloudwatch.GetMetricStatisticsInput{
  		StartTime:  &m.StartDate,
  		EndTime:    &m.EndDate,
  		MetricName: &name,
  		Namespace:  aws.String("AWS/Lambda"),
  		Period:     aws.Int64(int64(period(m.StartDate, m.EndDate).Seconds())),
  		Statistics: []*string{
  			aws.String("Sum"),
  		},
  		Dimensions: []*cloudwatch.Dimension{
  			{
  				Name:  aws.String("FunctionName"),
  				Value: &m.FunctionName,
  			},
  		},
  		Unit: aws.String(unit(name)),
  	})
  }
docs: // stats for function `name`.