translate"><span class="pre">&lt;%block&gt;</span></code> can only be defined once in a template – an error is raised if two blocks of the same
name occur anywhere in a single template, regardless of nesting.  A similar error is raised if a top level def
shares the same name as that of a block.</p></li>
<li><p>A named <code class="docutils literal notranslate"><span class="pre">&lt;%block&gt;</span></code> cannot be defined within a <code class="docutils literal notranslate"><span class="pre">&lt;%def&gt;