code: def __init__(
      self,
      trainer: BaseCBTrainerWithEval,
      feature_dim: int,
      policy=Policy,
  ):
      self._feature_dim = feature_dim
      self.trainer = trainer
      self.policy = policy
  
imports: import random
  from dataclasses import replace
  from typing import Any, Optional, Tuple
  import reagent.core.types
  import torch
  from reagent.core.types import CBInput
  from reagent.gym.policies.policy import Policy
  from reagent.gym.policies.samplers.discrete_sampler import GreedyActionSampler
  from reagent.gym.types import Sampler, Scorer
  from reagent.models.linear_regression import LinearRegressionUCB
  from reagent.training.cb.base_trainer import BaseCBTrainerWithEval
  from reagent.training.cb.linucb_trainer import LinUCBTrainer
  from reagent.training.parameters import LinUCBTrainerParameters
label_desc: Use image node_id 1 to create a new DynamicBanditAgent object  with example: obj = DynamicBanditAgent(trainer, feature_dim, policy)