he library to be unique and
mandatory and the title of a book should be required:</p>
<div class="highlight-yaml"><div class="highlight"><pre><span></span><span class="l l-Scalar l-Scalar-Plain">library</span><span class="p p-Indicator">:</span>
    <span class="l l-Scalar l-Scalar-Plain">table</span><span class="p p-Indicator">:</span> <span class="l l-Scalar l-Scalar-Plain">lib</span>
    <span class="l l-Scalar l-Scalar-Plain">label</span><span class="p p-Indicator">:</span> <span class="l l-Scalar l-Sca