code: def add_cms_link(self):
          
          intnote = record_get_field_values(self.record, '690',
                                            filter_subfield_code="a",
                                            filter_subfield_value='INTNOTE')
          if intnote:
              val_088 = record_get_field_values(self.record,
                                                tag='088',
                                                filter_subfield_code="a")
              for val in val_088:
                  if 'CMS' in val:
                      url = ('http://weblib.cern.ch/abstract?CERN-CMS' +
                             val.split('CMS', 1)[-1])
                      record_add_field(self.record,
                                       tag='856',
                                       ind1='4',
                                       subfields=[('u', url)])
docs: Special handling if record is a CMS NOTE.