code: def __init__(
      self, policy: RLPolicy, model: Model, gamma: float = 0.99
  ) -> None:
      self._policy = policy
      self._model = model
      self._gamma = gamma
      self._state_values = {}
  
imports: import pickle
  from functools import reduce
  from typing import List, Mapping, Sequence
  import torch
  from reagent.ope.estimators.sequential_estimators import Model, RLPolicy, State, ValueFunction
  from reagent.ope.estimators.types import Action, ActionDistribution, ActionSpace
  from reagent.ope.test.envs import Environment, PolicyLogGenerator
  from reagent.ope.utils import RunningAverage
label_desc: Use image node_id 1 to create a new TabularValueFunction object from inherited base classes: ValueFunction with example: obj = TabularValueFunction(policy, model, gamma)