/a> | <a class="reference internal" href="#grammar-token-sf-chrono_format_spec"><code class="xref docutils literal notranslate"><span class="pre">chrono_format_spec</span></code></a>)] &quot;}&quot;
<strong id="grammar-token-sf-arg_id"><span id="grammar-token-arg-id"></span>arg_id           </strong> ::=  <a class="reference internal" href="#grammar-token-sf-integer"><code class="xref docutils literal notranslate"><span class="pre">integer</span></code></a> | <a class="reference internal" href="#grammar-tok