如何获取自定义函数引用的单元格区域的值？

function FactorialFunction() {
  this.name = "test";
  this.maxArgs = 1;
  this.minArgs = 1;
  this.typeName = "FactorialFunction";
}
FactorialFunction.prototype = new GC.Spread.CalcEngine.Functions.Function();
FactorialFunction.prototype.evaluate = function (arg1, arg2) {
  //your own evaluate content
};
FactorialFunction.prototype.acceptsReference = function () {
  return true; //接受引用单元格区域
};
FactorialFunction.prototype.isContextSensitive = function () {
  return true;
};

var row = arg2.yf[0].row;
var col = arg2.yf[0].col;
var rowCount = arg2.yf[0].rowCount;
var colCount = arg2.yf[0].colCount;

var value = sheet.getValue(row, col);
var arrayValue = sheet.getArray(row, col, rowCount, colCount);

var factorial = new FactorialFunction();
sheet.addCustomFunction(factorial);
sheet.setFormula(0, 1, "=test(B6:D6)");