class_docstr: Custom Dataset wrapping language modeling sequences.
  
  Each sample will be retrieved by indexing the list of token_ids and their corresponding lengths.
  
  Input:
  ------
      params: `NameSpace` parameters
      data: `List[np.array[int]]
code: def __getitem__(self, index):
      return (self.token_ids[index], self.lengths[index])
  
file_path: H2O/h2o_flexgen/benchmark/third_party/transformers/examples/research_projects/distillation/lm_seqs_dataset.py
imports: import numpy
  import torch
  from torch.utils.data import Dataset
  from utils import logger
label_desc: Use image node_id 2 for calling the LmSeqsDataset obj's underlying member method code with example usage: obj.__getitem__(index) and returns: self,  self