'b'], ordered=True)
        >>> dtype2 = pd.CategoricalDtype(['x', 'y'], ordered=False)
        >>> c = pd.Categorical([0, 1], dtype=dtype1)
        >>> pd.CategoricalDtype._from_values_or_dtype(
        ...     c, ['x', 'y'], ordered=True, dtype=dtype2
        ... )
        Traceback (most recent call last):
            ...
        ValueError: Cannot specify `categories` or `ordered` together with
        `dtype`.

        The supplied dtype takes precedence over values' dtype:

        >>> pd.CategoricalDtype._from_values_or_dtype(c, dtype=dtype2)
        CategoricalDtype(categories=['x', 'y'], ordered=False, categories_dtype=object)
        Nrl