code: def dump_value_func(self, valfunc: ValueFunction) -> str:
      dump = ""
      for x in range(self.size[0]):
          for y in range(self.size[1]):
              dump += "{:6.3}".format(valfunc(State((x, y))))
          dump += "\n"
      return dump
  
imports: import logging
  import random
  from typing import Iterable, Optional, Sequence, Tuple
  import numpy
  import torch
  from reagent.ope.estimators.sequential_estimators import DMEstimator, DoublyRobustEstimator, EpsilonGreedyRLPolicy, IPSEstimator, MAGICEstimator, NeuralDualDICE, RewardProbability, RLEstimatorInput, State, StateDistribution, StateReward, ValueFunction
  from reagent.ope.estimators.types import Action, ActionSpace
  from reagent.ope.test.envs import Environment, PolicyLogGenerator
  from reagent.ope.trainers.rl_tabular_trainers import DPTrainer, DPValueFunction, EstimatedStateValueFunction, TabularPolicy
label_desc: Use image node_id 15 for calling the GridWorld obj's underlying member method code with example usage: obj.dump_value_func(valfunc) and returns: dump