class="k">break</span>
    <span class="n">Atom</span><span class="p">(</span><span class="s2">&quot;fail&quot;</span><span class="p">)</span><span class="o">.</span><span class="n">post_goal</span><span class="p">()</span>                        <span class="c1"># Post fail for backtracking over solutions</span>
<span class="n">B_var</span><span class="o">=</span><span class="n">Var</span><span class="p">()</span>                                         <span class="c1"># Create variable B</span>
<span cla