pan class="o">+</span> <span class="p">[</span><span class="s2">&quot;[END]&quot;</span><span class="p">]</span>
        <span class="k">for</span> <span class="n">smiles</span> <span class="ow">in</span> <span class="n">dataset</span>
    <span class="p">]</span>
    <span class="k">if</span> <span class="n">token2label</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
        <span class="n">token2label</span> <span class="o">=</span> <span class="n">smiles_utils</span