/*
 * call-seq:
 *  previous_element
 *
 * Returns the previous Nokogiri::XML::Element type sibling node.
 */
static VALUE previous_element(VALUE self)
{
  xmlNodePtr node, sibling;
  Data_Get_Struct(self, xmlNode, node);

  /*
   *  note that we don't use xmlPreviousElementSibling here because it's buggy pre-2.7.7.
   */
  sibling = node->prev;
  if(!sibling) return Qnil;

  while(sibling && sibling->type != XML_ELEMENT_NODE)
    sibling = sibling->prev;

  return sibling ? Nokogiri_wrap_xml_node(Qnil, sibling) : Qnil ;
}