you have created.</p>
<div class="sourceCode" id="cb17"><html><body><pre class="r"><span class="fu"><a href="https://rdrr.io/r/base/class.html">class</a></span>(<span class="no">plan</span>) <span class="kw">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html">c</a></span>(<span class="st">"plan"</span>, <span class="fu"><a href="https://rdrr.io/r/base/class.html">class</a></span>(<span class="no">plan</span>))
<span class="fu"><a href="https://rdrr.io/r/base/print.html">print</a></span>(<s