wxPython - InsertStretchableSpace() function in wx.ToolBar

import wx

class Example(wx.Frame):

    def __init__(self, *args, **kwargs):
        super(Example, self).__init__(*args, **kwargs)
        self.InitUI()

    def InitUI(self):
        self.locale = wx.Locale(wx.LANGUAGE_ENGLISH)
        self.toolbar = self.CreateToolBar()
        td = self.toolbar.AddTool(1, '', wx.Bitmap('sep.png'))
        te = self.toolbar.AddTool(2, '', wx.Bitmap('wrong.png'))
        tf = self.toolbar.AddTool(3, '', wx.Bitmap('right.png'))

        self.toolbar.Realize()
        self.Bind(wx.EVT_TOOL, self.OnOne, td)

        self.SetSize((350, 250))
        self.SetTitle('Undo redo')
        self.Centre()

    def OnOne(self, e):
        # insert stretchable space b / w separate 
        # and tick tool at position 1
        self.toolbar.InsertStretchableSpace(pos = 1)
        self.toolbar.Realize()

    def OnQuit(self, e):
        self.Close()


def main():

    app = wx.App()
    ex = Example(None)
    ex.Show()
    app.MainLoop()


if __name__ == '__main__':
    main()

import wx

class Example(wx.Frame):

    def __init__(self, *args, **kwargs):
        super(Example, self).__init__(*args, **kwargs)
        self.InitUI()

    def InitUI(self):
        self.locale = wx.Locale(wx.LANGUAGE_ENGLISH)
        self.toolbar = self.CreateToolBar()
        td = self.toolbar.AddTool(1, '', wx.Bitmap('sep.png'))
        te = self.toolbar.AddTool(2, '', wx.Bitmap('wrong.png'))
        tf = self.toolbar.AddTool(3, '', wx.Bitmap('right.png'))

        self.toolbar.Realize()
        self.Bind(wx.EVT_TOOL, self.OnOne, td)

        self.SetSize((350, 250))
        self.SetTitle('Undo redo')
        self.Centre()

    def OnOne(self, e):
        # insert stretchable space b / w tick and cross tool at position 2
        self.toolbar.InsertStretchableSpace(pos = 2)
        self.toolbar.Realize()

    def OnQuit(self, e):
        self.Close()


def main():

    app = wx.App()
    ex = Example(None)
    ex.Show()
    app.MainLoop()


if __name__ == '__main__':
    main()