strategy.</span>
<span class="r-wrn co"><span class="r-pr">#&gt;</span> <span class="warning">Warning: </span>No cost and/or effect defined, cannot find root strategy.</span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="va">new_tab</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/data.frame.html" class="external-link">data.frame</a></span><span class="op">(</span></span></span>
<span class="r-in"><span>  a <span class="op">=</span> <span 