tion-fixme-needs-rfc' class='section-header'><a href='#use-internal-module-hierarchies-for-organization-fixme-needs-rfc'>Use internal module hierarchies for organization. [FIXME: needs RFC]</a></h3>
<blockquote>
<p><strong>[FIXME]</strong>
- Referencing internal modules from the standard library is subject to
  becoming outdated.</p>
</blockquote>

<p>Internal module hierarchies (i.e., private submodules) may be used to
hide implementation details that are not part of the module&#39;s API.</p>

<p>For examp