code: def __init__(
      self, file_path: str, tokenizer: TokenizerSpec, **kwargs
  ):
      super().__init__(file_path, tokenizer, **kwargs)
  
      self._load_packed_dataset(file_path)
  
imports: import re
  from typing import List, Mapping, Optional
  import datasets
  import numpy
  import torch
  from datasets import load_dataset
  from nemo.collections.common.tokenizers.tokenizer_spec import TokenizerSpec
  from nemo.collections.nlp.data.language_modeling.megatron.dataset_utils import get_samples_mapping
  from nemo.collections.nlp.data.language_modeling.text_memmap_dataset import JSONLMemMapDataset
  from nemo.core.classes import Dataset
  from nemo.utils import logging
label_desc: Use image node_id 1 to create a new GPTSFTPackedDataset object from inherited base classes: GPTSFTDataset with example: obj = GPTSFTPackedDataset(file_path, tokenizer)