Raise an error if an option is not supported.

def raise_error_unsupported_categorical_option(option_name, option_value, layer_type, layer_name):
    """
    Raise an error if an option is not supported.
    """
    raise RuntimeError("Unsupported option %s=%s in layer %s(%s)" % (option_name, option_value,
        layer_type, layer_name))