import wx
import wx.lib.agw.genericmessagedialog as GMD

# Our normal wxApp-derived class, as usual
app = wx.App(0)

main_message = "Hello world! I am the main message."

dlg = GMD.GenericMessageDialog(None, main_message, "A Nice Message Box",
                               agwStyle=wx.ICON_INFORMATION|wx.OK)
                               
dlg.ShowModal()
dlg.Destroy()

app.MainLoop()