def on_cleanup_error(function, path, excinfo):
                click.secho("warning: failed to remove file or directory: {}\n"
                            "please delete it manually.".format(path),
                            fg="red")
def test_impl(n):
            df = pd.DataFrame({'A': ['aa', 'bb', 'aa', 'cc', 'cc']})
            return df.A.nunique()