/span>
<span class="r-in"><span>               xmiddle_var <span class="op">=</span> <span class="va">middle</span>,</span></span>
<span class="r-in"><span>               xupper_var <span class="op">=</span> <span class="va">upper</span>,</span></span>
<span class="r-in"><span>               xmax_var <span class="op">=</span> <span class="va">max</span>,</span></span>
<span class="r-in"><span>               y_var <span class="op">=</span> <span class="va">species</span>,</span></span>
<span class="r-in"><sp