code: def get_best_expr_cost(self, property: Property):
      winner = self._winner_exprs.get(property, None)
      if winner:
          return winner.cost
      else:
          return None
  
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 11 for calling the Group obj's underlying member method code with example usage: obj.get_best_expr_cost(property) and returns: winner, None