def _get_fontsize(size_name):
    """Return a fontsize based on matplotlib labels."""
    font_sizes = {
        "xx-small": 5.79,
        "x-small": 6.94,
        "small": 8.33,
        "medium": 10.0,
        "large": 12.0,
        "x-large": 14.4,
        "xx-large": 17.28,
        "larger": 12.0,
        "smaller": 8.33,
    }
    return font_sizes[size_name]