class MyFrame(wx.Frame):

            def __init__(self, parent):

                wx.Frame.__init__(self, parent, title='InfoBar!')                
        
                self.infoBar = wx.InfoBar(self)
    
                sizer = wx.BoxSizer(wx.VERTICAL)
                sizer.Add(self.infoBar, wx.SizerFlags().Expand())
                
                # ... add other frame controls to the sizer ...
                self.SetSizer(sizer)
        
    
            def SomeMethod(self):
        
                self.infoBar.ShowMessage("Something happened", wx.ICON_INFORMATION)