s="argument lambda-list-keyword">&amp;OPTIONAL</li>    <li class="argument">POSITION</li>  </ul>  <a class="source-link" href="https://shinmera.com/project/array-utils/blob/e71aaf14be270d4aa1e5ba6fa9319e2de776dda0/utils.lisp#L241">Source</a>  </header> <div class="docstring"><pre>Appends all elements of the sequence at position of the vector and returns it.
This is potentially very costly as all elements after the given position
need to be shifted back as per ARRAY-SHIFT.</pre></div> </article> </li>  <li> 