def test_not_set_subset_X(matrix_type, subset_func):
    adata = ad.AnnData(matrix_type(asarray(sparse.random(20, 20))))
    init_hash = joblib.hash(adata)
    orig_X_val = adata.X.copy()
    while True:
        subset_idx = slice_subset(adata.obs_names)
        if len(adata[subset_idx, :]) > 2:
            break
    subset = adata[subset_idx, :]

    subset = adata[:, subset_idx]

    internal_idx = _normalize_index(
        subset_func(np.arange(subset.X.shape[1])), subset.var_names
    )
    assert subset.is_view
    subset.X[:, internal_idx] = 1
    assert not subset.is_view
    assert not np.any(asarray(adata.X != orig_X_val))

    assert init_hash == joblib.hash(adata)
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
        }