span class="kd">public</span> <span class="kd">func</span> <span class="n">mapError</span><span class="o">&lt;</span><span class="kt">E</span><span class="o">&gt;</span><span class="p">(</span><span class="n">_</span> <span class="nv">transform</span><span class="p">:</span> <span class="p">(</span><span class="kt">Error</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="kt">E</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="kt">DataResponse</span> <span class="