code: def __init__(self, doc_id, features, video_length=None, quality=None):
      super(SingleClusterIEvVideo, self).__init__(
          doc_id=doc_id,
          features=features,
          cluster_id=0,  # single cluster.
          video_length=video_length,
          quality=quality,
      )
  
file_path: ray/python/ray/rllib/examples/env/recommender_system_envs_with_recsim.py
imports: from recsim import choice_model
  from recsim.environments import long_term_satisfaction, interest_evolution, interest_exploration
  from ray.rllib.env.wrappers.recsim import make_recsim_env
  from ray.tune import register_env
label_desc: Use image node_id 1 to create a new SingleClusterIEvVideo object from inherited base classes: iev with example: obj = SingleClusterIEvVideo(doc_id, features, video_length, quality)