def test_views():
    X = np.array(X_list)
    adata = ad.AnnData(X, obs=obs_dict, var=var_dict, uns=uns_dict, dtype="int32")

    assert adata[:, 0].is_view
    assert adata[:, 0].X.tolist() == np.reshape([1, 4, 7], (3, 1)).tolist()

    adata[:2, 0].X = [0, 0]

    assert adata[:, 0].X.tolist() == np.reshape([0, 0, 7], (3, 1)).tolist()

    adata_subset = adata[:2, [0, 1]]

    assert adata_subset.is_view
    # now transition to actual object
    adata_subset.obs["foo"] = range(2)
    assert not adata_subset.is_view

    assert adata_subset.obs["foo"].tolist() == list(range(2))
def deadlines_for_courses(cls, course_keys):
        """
        Retrieve verification deadlines for particular courses.

        Arguments:
            course_keys (list): List of `CourseKey`s.

        Returns:
            dict: Map of course keys to datetimes (verification deadlines)

        """
        all_deadlines = cache.get(cls.ALL_DEADLINES_CACHE_KEY)
        if all_deadlines is None:
            all_deadlines = {
                deadline.course_key: deadline.deadline
                for deadline in VerificationDeadline.objects.all()
            }
            cache.set(cls.ALL_DEADLINES_CACHE_KEY, all_deadlines)

        return {
            course_key: all_deadlines[course_key]
            for course_key in course_keys
            if course_key in all_deadlines
        }