def adata():
    adata = ad.AnnData(np.zeros((100, 100)))
    adata.obsm["o"] = np.zeros((100, 50))
    adata.varm["o"] = np.zeros((100, 50))
    return adata
def test_regex_bad_pattern():
    """Regex error raised immediately when regex input parser is created."""
    assert_raises(re.error, inputs.regex, '[')