import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk

class PyApp(Gtk.Window):
    def __init__(self):
        super(PyApp, self).__init__()

        self.set_title("Boton")
        self.set_position(Gtk.WindowPosition.CENTER_ALWAYS)
        self.set_size_request(250, 200)

        def button_cb(widget):
            print('click')

        button = Gtk.Button(label="Boton")
        fixed = Gtk.Fixed()
        fixed.put(button, 20, 30)
        button.connect('clicked', button_cb)

        self.connect("destroy", Gtk.main_quit)

        self.add(fixed)
        self.show_all()


PyApp()
Gtk.main()
