ise</span> <span class="ne">IOError</span><span class="p">(</span><span class="s1">'Not a gzipped file'</span><span class="p">)</span>

    <span class="n">_</span><span class="p">,</span> <span class="n">flag</span><span class="p">,</span> <span class="n">_</span> <span class="o">=</span> <span class="n">struct</span><span class="o">.</span><span class="n">unpack</span><span class="p">(</span><span class="s2">"&lt;BBIxx"</span><span class="p">,</span> <span class="n">gf</span><span class="o">.</span><span 