docs: def save(self, obj):
          """Required functionality."""
          if not obj.id:
              obj.id = uuid()
  
          index_names = obj.__class__.index_names() or []
          index_dict = obj.indexes() or {}
          index_name_values = [
              (key, index_dict.get(key, ''))
              for key in index_names
          ]
  
          write_rec(
              obj.__class__.get_table_name(),
              obj.id,
              obj.to_data(),
              index_name_values
          )