@ndb.transactional
    def unassign(self, user):
        """Unassigns the given user from this question.

        Args:
            user: datastore_types.IM: The user who will no longer be answering
                this question.
        """
        question = self.key.get()
        if user in question.assignees:
            question.assignees.remove(user)
            question.put()
dataset/ETHPy150Open googlearchive/appengine-crowdguru-python/guru.py/Question.unassign/original