class_docstr: The low-level interface dataset class
  
  Args:
      path_prefix (str): The index (.idx) and data (.bin) prefix
  
      multimodal (bool, optional): Whether the dataset is multimodal. Defaults to False.
class_docstr_tok: ["The","low-level","interface","dataset","class","Args",":","path_prefix","(","str",")",":","The","index","(",".idx",")","and","data","(",".bin",")","prefix","multimodal","(","bool",",","optional",")",":","Whether","the","dataset","is","multimodal",".","Defaults","to","False","."]
docstr: Clean up the object
          
docstr_tok: ["Clean","up","the","object"]
code: def __del__(self) -> None:
      """Clean up the object"""
      if self.bin_buffer_mmap is not None:
          self.bin_buffer_mmap._mmap.close()
      del self.bin_buffer_mmap
      del self.index
  
imports: import logging
  import os
  import shutil
  import struct
  import time
  from enum import Enum
  from functools import lru_cache
  from itertools import accumulate
  from types import TracebackType
  from typing import List, Optional, Tuple, Type, Union
  import numpy
  import torch
  from megatron.core.datasets.utils import log_single_rank
label_desc: Use image node_id 5 for calling the MMapIndexedDataset obj's underlying member method code with example usage: obj.__del__() without return types