主题：为何此定义函数在命令窗口测试错误？

下面是帮助文件中的一个自定义sum函数，为何在定义后调用显示“自定义函数sum执行出错”

Dim Code As string
Code = "Dim Val1 As Integer = 1" & vbcrlf
Code = Code & "Dim Val2 As Integer = 2" & vbcrlf
Code = Code & "Dim Sum As Integer = Val1 + Val2" & vbcrlf
Code = Code & "Return Sum"
Functions.Add("Sum",Code)
Functions.Complie()