ss="keyword">double</span> <span class="identifier">x</span> <span class="special">)</span>
  <span class="special">:</span> <span class="identifier">pbase0_type</span><span class="special">(</span> <span class="number">0.2</span> <span class="special">)</span>
  <span class="special">,</span> <span class="identifier">pbase1_type</span><span class="special">()</span>
  <span class="special">,</span> <span class="identifier">pbase2_type</span><span class="special">(</span> <span class="special">-</span><span