Can wx.DateTime objects be stored with Python shelves?

I'm writing a todo application, which needs to be able to store due dates on disk. I'm using shelves to accomplish this. However, when I store my tree structure containing wx.DateTime objects (created with wx.DatePickerCtrl), it hangs. If I remove the dates from the tree structure, the problem goes away.

So, is there a problem with storing wx.DateTime objects with shelves in general, or am I doing something wrong?

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Christer Enfors