code: def look_for_hdl(citation_elements):
      
      for el in list(citation_elements):
          matched_hdl = re_hdl.finditer(el['misc_txt'])
          for match in reversed(list(matched_hdl)):
              hdl_el = {'type': 'HDL',
                        'hdl_id': match.group('hdl_id'),
                        'misc_txt': el['misc_txt'][match.end():]}
              el['misc_txt'] = el['misc_txt'][0:match.start()]
              citation_elements.insert(citation_elements.index(el) + 1, hdl_el)
docs: Looks for handle identifiers in the misc txt of the citation elements
  
         When finding an hdl, creates a new HDL element.
         @param citation_elements: (list) elements to process