a><span class="lineno">   77</span>&#160;</div><div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;        <span class="keyword">using</span> value_type = <span class="keyword">typename</span> D::value_type;</div><div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;        gil_function_requires&lt;PixelValueConcept&lt;value_type&gt;&gt;();</div><div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160;</div><div class="line"><a name="l00