AuiNotebook disable move first tab

I want to make the first tab disable the sort and drag property

class TestPanel(wx.Panel):
    def __init__(self, parent):
        wx.Panel.__init__(self, parent, -1, style=wx.NO_BORDER)

        self.nb = aui.AuiNotebook(self, id=wx.ID_ANY, agwStyle = aui.AUI_NB_TOP | aui.AUI_NB_TAB_MOVE | aui.AUI_NB_SCROLL_BUTTONS | aui.AUI_NB_CLOSE_ON_ALL_TABS | aui.AUI_NB_MIDDLE_CLICK_CLOSE)
        page = wx.TextCtrl(self.nb, -1, 'Main content window', style=wx.TE_MULTILINE)
        self.nb.AddPage(page, "Welcome")
        for num in range(1, 5):
            page = wx.TextCtrl(self.nb, -1, "This is page %d" % num ,
                               style=wx.TE_MULTILINE)
            self.nb.AddPage(page, "Tab Number %d" % num)
        self.nb.SetCloseButton(0, False)
        self.nb.Bind(aui.EVT_AUINOTEBOOK_BEGIN_DRAG, self.DragTab)
        self.nb.Bind(aui.EVT_AUINOTEBOOK_PAGE_CLOSE, self.onClosePage)
        sizer = wx.BoxSizer()
        sizer.Add(self.nb, 1, wx.EXPAND)
        self.SetSizer(sizer)
        wx.CallAfter(self.nb.SendSizeEvent)

    def onClosePage(self, event):
        event.Skip()
        print(self.nb.GetPageCount())
        if self.nb.GetPageCount() <= 3:
            # Prevent last tab from being closed
            self.nb.ToggleWindowStyle(aui.AUI_NB_CLOSE_ON_ACTIVE_TAB)

    def DragTab(self, evn):
        page_idx = evn.GetSelection()
        if 0 == page_idx:
            return False