code: def add_install_button(self, grid_lang, row, column):
          
          btn = self.button_with_label('<b>Install more...</b>')
          if row == 0 and column == 0:
              grid_lang.add(btn)
          else:
              grid_lang.attach(btn, column, row, 1, 1)
          btn.connect("clicked", self.parent.install_btn_clicked)
          return btn
docs: Add button that opens the window for installing more assistants