def METHOD_NAME(cls, string, source):
    try:
        width_str, color_str = (part.strip() for part in string.split(','))
    except ValueError:
        raise ParseError('Expecting stroke width and color separated by a '
                         'comma')
    width = Dimension.from_string(width_str)
    color = Color.from_string(color_str)
    return cls(width, color)