n_sub_domain</span><span class="p">(</span><span class="n">self</span><span class="p">,</span><span class="n">d2</span><span class="p">)&amp;</span>
  <span class="k">result</span><span class="p">(</span><span class="n">domain</span><span class="p">)</span>
  <span class="c">!! Returns a difference between two domain instances.</span>
  <span class="k">class</span><span class="p">(</span><span class="n">domain_type</span><span class="p">),</span><span class="k">intent</span><span class="p">(</span><span cla