import wx

class MainFrame(wx.Frame):
    def __init__(self, parent):
        super(MainFrame, self).__init__(parent)
        self.text = wx.TextCtrl(self)
        self.button = wx.Button(self, label="Mehet")
        self.button.Bind(wx.EVT_BUTTON, self.OnClickButton)
        vbox = wx.BoxSizer(wx.VERTICAL)
        vbox.Add(self.text)
        vbox.Add(self.button)
        self.SetSizer(vbox)
        self.Layout()
    def OnClickButton(self, event):
        self.text.SetValue("42")


class ButtonApp(wx.App):
    def OnInit(self):
        frame = MainFrame(None)
        frame.Show()
        return True

app = ButtonApp()
app.MainLoop()