grid_sizer_1.AddMany([(self.button_last_page, 0, wx.ALIGN_CENTER_HORIZONTAL |
    wx.ALIGN_CENTER_VERTICAL), (self.button_up, 0, wx.ALIGN_BOTTOM | wx.
    ALIGN_CENTER_HORIZONTAL), (self.button_next_page, 0, wx.
    ALIGN_CENTER_HORIZONTAL | wx.ALIGN_CENTER_VERTICAL), (self.button_left,
    0, wx.ALIGN_RIGHT | wx.ALIGN_CENTER_VERTICAL), (self.button_select, 0, 
    wx.ALIGN_CENTER_HORIZONTAL | wx.ALIGN_CENTER_VERTICAL), (self.
    button_right, 0, wx.ALIGN_CENTER_VERTICAL), (wx.StaticText(self, -1, ''
    ), 0, wx.EXPAND), (self.button_down, 0, wx.ALIGN_CENTER_HORIZONTAL)])
wxPython GridSizer - dealing with empty cells