_pairs</span><span class="p">,</span>
    <span class="n">species</span><span class="o">=</span><span class="s1">&#39;receptor&#39;</span><span class="p">,</span>
    <span class="n">secretory_key</span><span class="o">=</span><span class="s1">&#39;Secreted Signaling&#39;</span><span class="p">,</span>
    <span class="n">contact_key</span><span class="o">=</span><span class="s1">&#39;Cell-Cell Contact&#39;</span><span class="p">,</span>
    <span class="n">secretory_radius</span><span class="o">=</span