<document source="test data">
    <system_message level="3" line="1" source="test data" type="ERROR">
        <paragraph>
            Error in "mathml" directive:
            invalid option value: (option: "mstyle"; value: 'badly formatted field list')
            invalid literal for fieldlist.
        <literal_block xml:space="preserve">
            .. mathml::
               :mstyle: badly formatted field list