Sort wordpress categories by description field

gistfile1.php

  <?php
  $resource_terms = get_terms( 'section' );
  // Sort terms by description field
  function description_compare($a, $b) {
    return $a->description - $b->description;
  }
  usort($resource_terms, "description_compare");
  ?>
  <div class="resource-filter">
    <a href="#" class="resource-filter-term" data-filter="article" data-filter-by=".resource">All</a>
  <?php foreach( $resource_terms as $term ): ?>
    <a href="#" class="resource-filter-term" data-filter="article" data-filter-by=".<?php echo $term->slug ?>"><?php echo $term->name ?></a>
  <?php endforeach; ?>
  </div>