docs: def _val_fs_regex(self, record, hist=None):
          """
          Perform field-specific validation regex
  
          :param dict record: dictionary of values to validate
          :param dict hist: existing input of history values
          """
  
          record, hist = self.data_regex_method(fields_list=self.fields,
                                                mongo_db_obj=self.mongo,
                                                hist=hist,
                                                record=record,
                                                lookup_type='fieldSpecificRegex')
          return record, hist