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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _create_wx_app():
 """ Creates a wx.App instance if it has not been created sofar. """

    wxapp = wx.GetApp()
    if wxapp is None:
        wxapp = wx.App(False)
        wxapp.SetExitOnFrameDelete(True)
        # retain a reference to the app object so it does not get garbage
        # collected and cause segmentation faults
        _create_wx_app.theWxApp = wxapp