called on save button

def on_save(self, event):
        '''called on save button'''
        dlg = wx.FileDialog(None, self.settings.get_title(), '', "", '*.*',
                            wx.FD_SAVE | wx.FD_OVERWRITE_PROMPT)
        if dlg.ShowModal() == wx.ID_OK:
            self.settings.save(dlg.GetPath())