ar</span> <span class="o">=</span> <span class="n">nn</span><span class="o">.</span><span class="n">Linear</span><span class="p">(</span><span class="n">input_dim</span><span class="p">,</span> <span class="n">hidden_dim</span><span class="p">)</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">layer</span> <span class="o">=</span> <span class="n">layers</span><span class="o">.</span><span class="n">MessagePassing</span><span class="p">(</span><span class="n">hidden_dim</span