<spanclass="n">tank_levels</span><spanclass="o">=</span><spanclass="n">get_levels</span><spanclass="p">(</span><spanclass="n">all_tanks</span><spanclass="p">)</span><spanclass="c1"># retrieve levels for every iteration</span>
<spanclass="k">for</span><spanclass="n">tank_id</span><spanclass="p">,</span><spanclass="n">level</span><spanclass="ow">in</span><spanclass="n">tank_levels</span><spanclass="o">.</span><spanclass="n">items</span><spanclass="p">():</span><spanclass="c1"># save the levels!</span>
<spanclass="k">for</span><spanclass="n">tank_id</span><spanclass="p">,</span><spanclass="n">level</span><spanclass="ow">in</span><spanclass="n">tank_levels</span><spanclass="o">.</span><spanclass="n">items</span><spanclass="p">():</span><spanclass="c1"># iterate over all tank levels</span>
<spanclass="n">levels</span><spanclass="p">[</span><spanclass="n">tank_id</span><spanclass="p">]</span><spanclass="o">.</span><spanclass="n">append</span><spanclass="p">(</span><spanclass="n">level</span><spanclass="p">)</span><spanclass="c1"># save the levels!</span>
<spanclass="n">final_tank</span><spanclass="o">.</span><spanclass="n">fill_tank</span><spanclass="p">()</span><spanclass="c1"># open valves and let the water through to our last tank!</span>