HarmonyOS 函数中调用动态import，如何设定返回类型？

请参考：

function DynamicNumber() :number{
  let number1:number = 0;
  import('../Calc').then((ns:ESObject) => {
    let calc:ESObject = new ns.Calc();  // 实例化类Calc
    number1 = calc.instanceAdd(10, 11);  // 调用成员函数instanceAdd()
    console.log('Index DynamicImport I am harlibrary in staticAdd, %d + %d = %d', 10, 11, number1);
    return number1;
  });
  return number1;
}
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