ll not raise
   <code class="code"><span class="constructor">Invalid_argument</span></code>, but you should still avoid calling <code class="code">finalise</code>
   on lazy values.
</p><p>

   The results of calling <a href="String.html#VALmake"><code class="code"><span class="constructor">String</span>.make</code></a>, <a href="Bytes.html#VALmake"><code class="code"><span class="constructor">Bytes</span>.make</code></a>, <a href="Bytes.html#VALcreate"><code class="code"><span class="constructor">Bytes</sp