styler.hide(level=[0,1]).relabel_index(["binary6", "binary7"])
        ...  # doctest: +SKIP
                  col
        binary6     6
        binary7     7

        Defining a formatting function which uses an enumeration counter. Also note
        that the value of the index key is passed in the case of string labels so it
        can also be inserted into the label, using curly brackets (or double curly
        brackets if the string if pre-formatted),

        >>> df = pd.DataFrame({"samples": np.random.rand(10)})
        >>> styler = df.loc[np.random.randint(0,10,3)].style
        >>> styler.relabel_index([f"sample{i+1} ({{}})" for i in range(3)])
        ...  # doctest: +SKIP
                         samples
        sample1 (5)     0.315811
        sample2 (0)     0.495941
        sample3 (2)     0.067946
        r