 find the radius of the bounding circle of the vertex coordinates in the graph.</span>

<span class="sd">        Returns:</span>
<span class="sd">            float: The radius of the bounding circle.</span>

<span class="sd">        &quot;&quot;&quot;</span>
        <span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">coordinates</span><span class="p">:</span>
            <span class="k">return</span> <span class="mi">0</span>

        <sp