anchor.diff:      function Add : TmGroupByDef;
       function Count : integer;
       function Get(const aIndex : integer): TmGroupByDef;
  +    procedure Clear;
     end;
   
     TmCalculationKind = (ckSum, ckCount, ckMin, ckMax, ckFormula);
  
positive.code:   InternalCalculate(false);
  end;
  
  function TmPivoter.GetRecords(const aVerticalKeys, aHorizontalKeys: TStringList): TCardinalList;
  var
    tmpHor, tmpVer : String;
  
negative.code:   Result := FList.Items[aIndex] as TmGroupByDef;
  end;
  
  procedure TmGroupByDefs.Clear;
  begin
    FList.Clear;
  end;
  
  { TmGroupByDef }
  
  constructor TmGroupByDef.Create;
  