docstr: Reads a single text observation.
docstr_tok: ["Reads","a","single","text","observation","."]
code: def __getitem__(self, idx: int) -> Dict:
      """Reads a single text observation."""
      sample = super().__getitem__(idx)
      sample["reward_model_prompt_text"] = TEXT_SEPARATOR.join(
          self.get_chained_prompt_text_list(idx)
      )
      return sample
  
file_path: h2o-llmstudio/llm_studio/src/datasets/text_rlhf_modeling_ds.py
imports: import logging
  from typing import Any, Dict, List
  import numpy
  import pandas
  import torch
  from llm_studio.src.datasets.text_causal_language_modeling_ds import CustomDataset
  from llm_studio.src.datasets.text_utils import TEXT_SEPARATOR
label_desc: Use image node_id 2 for calling the CustomDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: sample