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():
            A = np.array([1., 2., 3.])
            A[0] = 4.0
            df = pd.DataFrame({'A': A})
            return df.A.var()