Setup toolbar

def setup_toolbar(self):
        """Setup toolbar"""
        load_button = create_toolbutton(self, text=_('Import data'),
                                        icon=ima.icon('fileimport'),
                                        triggered=lambda: self.import_data())
        self.save_button = create_toolbutton(self, text=_("Save data"),
                            icon=ima.icon('filesave'),
                            triggered=lambda: self.save_data(self.filename))
        self.save_button.setEnabled(False)
        save_as_button = create_toolbutton(self,
                                           text=_("Save data as..."),
                                           icon=ima.icon('filesaveas'),
                                           triggered=self.save_data)
        reset_namespace_button = create_toolbutton(
                self, text=_("Remove all variables"),
                icon=ima.icon('editdelete'), triggered=self.reset_namespace)

        return [load_button, self.save_button, save_as_button,
                reset_namespace_button]