nsform of FORM document model
           into NITRO element model (second layer) which later will be
           transformed into HTML5 encoding (first layer).</p>
    </section>
    <section>
        <h3>FORM PROVIDER</h3>
        <p>The input FORM module expects forms to expose the following API.</p>
        <h4>Module:id() -> tuple().</h4>
        <p>Should return the default business object instance for this document form.</p>
        <figure><code> id() -> #'Document'{}.</code></figure>
        <h4>Modu