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<?phpfunction modify_blockquote_($match) {	return '<blockquote>'.$match[1].'</blockquote><span>Something</span>';}add_action('the_content', 'modify_blockquote');function modify_blockquote($content) {	return preg_replace_callback('/\<blockquote\>(.*?)\<\/blockquote\>/si', 'modify_blockquote_', $content);}?>