class_docstr: Test run of the DynamitBandits environment and agent.
  Check the coefs of the model has been updated.
  Get the accumulated rewards and accumulated regrets.
code: def setUp(
      self,
      feature_dim: int = 3,
      num_unique_batches: int = 10,
      batch_size: int = 4,
      num_arms_per_episode: int = 2,
  ):
      self.feature_dim = feature_dim
      self.num_unique_batches = num_unique_batches
      self.batch_size = batch_size
      self.num_arms_per_episode = num_arms_per_episode
  
imports: import unittest
  import torch
  from reagent.evaluation.cb.run_synthetic_bandit import run_dynamic_bandit_env
label_desc: Use image node_id 1 for calling the TestSyntheticBandit obj's underlying member method code with example usage: obj.setUp(feature_dim, num_unique_batches, batch_size, num_arms_per_episode) without return types