我无法让tkSimpleDialog在python中工作

Question

我有以下python测试程序。当我运行它时，我希望能够点击＆＃34;对话框＆＃34;菜单并选择＆＃34;显示对话框＆＃34;并弹出对话框。相反，我得到：

<img>

正如你所知，这是在运行python 2.7的Mac上。

Exception in Tkinter callback
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1532, in __call__
    return self.func(*args)
  File "testdialogs.py", line 13, in dialog_show
    result = tkSimpleDialog.askstring('Result', 'Where to next?')
AttributeError: 'module' object has no attribute 'askstring'