This is a convenience function for returning the entry in the Argument by index. It is most applicable when a single metric or a single KPI is used in the calculation and can simplify the complexity of the formula. For example the following are equivalent expressions when a single metric is used in the KPI calculation:
var issues = metrics.get();
var issues = metrics.get('Critical Issues'); //find a metric by name
var issues = metrics.get(0); //the first metric by index
Note that the returned list of facts may include multiple data points depending on previous date/time filters and the input data set. By default metrics data for the day is provided to the KPI calculations and for the last 30 days for KPI inputs. Both of these defaults can be changed on a per KPI basis.