from wxPython.wx import *

class MiaApp(wxApp):
    def OnInit(self):
        dlg = wxDialog(None, -1, "")

        ID_BTN = wxNewId()
        btn = wxButton(dlg, ID_BTN, "Premimi!")
        EVT_BUTTON(self, ID_BTN, self.OnClick)

        dlg.ShowModal()
        dlg.Destroy()
        return 1

    def OnClick(self, event):
        wxMessageBox("Il pulsante è stato premuto")

app = MiaApp()
app.MainLoop()