 are suffixed to a URL, like so:
"request?para1=value1&amp;para2=value2". The first parameter is suffixed with "?"
and all others after that "&amp;". This function will determine the correct
suffix based on the presence of "&amp;" in the request.</p>
    </div>

    <pre class="usage"><span class='fu'>add_parameter</span><span class='op'>(</span>
  <span class='va'>request</span>,
  <span class='va'>parameter_name</span>,
  <span class='va'>parameter_value</span>,
  .combine <span class='op'>=</span> <span 