code: def add_expr_cost(self, expr: GroupExpression, property, cost):
      existing_winner = self._winner_exprs.get(property, None)
      if not existing_winner or existing_winner.cost > cost:
          self._winner_exprs[property] = Winner(expr, cost)
  
imports: from __future__ import annotations
  from typing import Dict, List
  from evadb.constants import UNDEFINED_GROUP_ID
  from evadb.optimizer.group_expression import GroupExpression
  from evadb.optimizer.property import Property
  from evadb.utils.logging_manager import logger
label_desc: Use image node_id 12 for calling the Group obj's underlying member method code with example usage: obj.add_expr_cost(expr, property, cost) without return types