PivotGroup constructor
      
      PivotGroup({ 
    
    
- DataSourceColumnReference? dataSourceColumnReference,
 - PivotGroupLimit? groupLimit,
 - PivotGroupRule? groupRule,
 - String? label,
 - bool? repeatHeadings,
 - bool? showTotals,
 - String? sortOrder,
 - int? sourceColumnOffset,
 - PivotGroupSortValueBucket? valueBucket,
 - List<
PivotGroupValueMetadata> ? valueMetadata, 
Implementation
PivotGroup({
  this.dataSourceColumnReference,
  this.groupLimit,
  this.groupRule,
  this.label,
  this.repeatHeadings,
  this.showTotals,
  this.sortOrder,
  this.sourceColumnOffset,
  this.valueBucket,
  this.valueMetadata,
});