<document source="test data">
    <paragraph>
        A class directive with nowhere to go.
    <section classes="system-messages">
        <title>
            Docutils System Messages
        <system_message level="2" line="3" source="test data" type="WARNING">
            <paragraph>
                Error in "class" directive: there is no following block element for which a class can be specified.
            <literal_block xml:space="preserve">
                .. class:: myclass
