def class_to_value(axis, ufo_class):
    """
    >>> class_to_value('wdth', 7)
    125
    """
    if axis == "wght":
        # 600.0 => 600, 250 => 250
        return int(ufo_class)
    elif axis == "wdth":
        return WIDTH_CLASS_TO_VALUE[int(ufo_class)]

    raise NotImplementedError