docs: def find_by_index(self, cls, index_name, value):
          """Required functionality."""
          table_name = cls.get_table_name()
          index_name_vals = [(index_name, value)]
  
          final_results = []
          for db_result in read_by_indexes(table_name, index_name_vals):
              obj = cls.from_data(db_result['value'])
              final_results.append(obj)
  
          return final_results