code: def init_app(self, app, entry_point_group='invenio_celery.tasks',
                   **kwargs):
          
          self.init_config(app)
          self.celery = FlaskCeleryExt(app).celery
          self.entry_point_group = entry_point_group
          app.extensions['invenio-celery'] = self
docs: Initialize application object.