def test_set_obsm_key(adata):
    init_hash = joblib.hash(adata)

    orig_obsm_val = adata.obsm["o"].copy()
    subset_obsm = adata[:50]
    assert subset_obsm.is_view
    subset_obsm.obsm["o"] = np.ones((50, 20))
    assert not subset_obsm.is_view
    assert np.all(adata.obsm["o"] == orig_obsm_val)

    assert init_hash == joblib.hash(adata)
def union(matches, root, cwd):
    """Union a list of matchers.

    If the list is empty, return nevermatcher.
    If the list only contains one non-None value, return that matcher.
    Otherwise return a union matcher.
    """
    matches = list(filter(None, matches))
    if len(matches) == 0:
        return nevermatcher(root, cwd)
    elif len(matches) == 1:
        return matches[0]
    else:
        return unionmatcher(matches)