lass="p">,</span> <span class="n">block_size</span><span class="p">)</span>
        <span class="k">if</span> <span class="n">block_size</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
            <span class="n">left_mats</span> <span class="o">=</span> <span class="kc">None</span>
            <span class="n">right_mats</span> <span class="o">=</span> <span class="kc">None</span>
            <span class="n">vec</span> <span class="o">=</span> <span class="n">np</span><spa