Method then

celery/result.py:114–116

(self, callback, on_error=None, weak=False)

        self._ignored = value

    def then(self, callback, on_error=None, weak=False):
        self.backend.add_pending_result(self, weak=weak)
        return self.on_ready.then(callback, on_error)

    def _on_fulfilled(self, result):
        self.backend.remove_pending_result(self)