idirectionalindextype-generator-element-index_-bidirectionalindextype-flatten">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-generator-element_-collectiontype-index_-bidirectionalindextype-generator-element-index_-bidirectionalindextype-flatten">func flatten()</a>
        
<div class="comment collapse" id="comment-func-generator-element_-collectiontype-index_-bidirectionalindextype-generator-element-index_-bidirectionalindextype-flatten"><div class="p">
    <p>A concatenation of the ele