$the_content = $post->post_content;

        $the_class = preg_match('~flex-video~', $the_content, $class);

        print_r($class['0']);

        if($class['0'] == 'flex-video'){
            $div_height = preg_match('~<iframe.*height=("[0-9]*")~', $the_content, $height_replace);

            $ppost = preg_replace('~class="flex-video"~', 'class="flex-video" width='.$height_replace['0'].'',  $the_content);

            echo $ppost;
        }