def test_drop_obs_column():
    adata = ad.AnnData(np.array(X_list), obs=obs_dict, dtype="int32")

    subset = adata[:2]
    assert subset.is_view
    # returns a copy of obs
    assert subset.obs.drop(columns=["oanno1"]).columns.tolist() == ["oanno2", "oanno3"]
    assert subset.is_view
    # would modify obs, so it should actualize subset and not modify adata
    subset.obs.drop(columns=["oanno1"], inplace=True)
    assert not subset.is_view
    assert subset.obs.columns.tolist() == ["oanno2", "oanno3"]

    assert adata.obs.columns.tolist() == ["oanno1", "oanno2", "oanno3"]
def _file_name_to_batch_number(example_file_name):
    """Parses batch number from file.

    :param example_file_name: See doc for `find_example_file`.
    :return: batch_number: Integer.
    :raises: ValueError: if batch number cannot be parsed from file name.
    """

    pathless_file_name = os.path.split(example_file_name)[-1]
    extensionless_file_name = os.path.splitext(pathless_file_name)[0]
    return int(extensionless_file_name.split('input_examples_batch')[-1])