"special">)</span>
      <span class="special">:</span> <span class="identifier">a</span><span class="special">(</span><span class="identifier">a</span><span class="special">),</span> <span class="identifier">b</span><span class="special">(</span><span class="identifier">b</span><span class="special">)</span>
    <span class="special">{}</span>

    <span class="keyword">double</span> <span class="identifier">a</span><span class="special">;</span>
    <span class="keyword">double</span> <span class="identif