class_docstr: This class is a data structure to keep the content in the index.json file for sharded checkpoint.
  
  Example:
      >>> index = CheckpointIndexFile.from_file('model.index.json')
      >>> index.append_metadata('model_type', 'bert')
      >>> index.append_weight_map('bert.embeddings.word_embeddings.weight', 'model_0001-of-0002.bin')
      >>> index.export('new_index.json')
class_docstr_tok: ["This","class","is","a","data","structure","to","keep","the","content","in","the","index.json","file","for","sharded","checkpoint",".","Example",":",">",">",">","index","=","CheckpointIndexFile.from_file","(","'model.index.json","'",")",">",">",">","index.append_metadata","(","'model_type","'",",","'bert","'",")",">",">",">","index.append_weight_map","(","'bert.embeddings.word_embeddings.weight","'",",","'model_0001-of-0002.bin","'",")",">",">",">","index.export","(","'new_index.json","'",")"]
docstr: Append a weight map entry to the index file.
  
  Args:
      param_name (str): name of the parameter.
      shard_file (str): name of the shard file.
docstr_tok: ["Append","a","weight","map","entry","to","the","index","file",".","Args",":","param_name","(","str",")",":","name","of","the","parameter",".","shard_file","(","str",")",":","name","of","the","shard","file","."]
code: def append_weight_map(self, param_name: str, shard_file: str):
      """
      Append a weight map entry to the index file.
  
      Args:
          param_name (str): name of the parameter.
          shard_file (str): name of the shard file.
      """
      self.weight_map[param_name] = shard_file
  
file_path: colossalai/colossalai/checkpoint_io/index_file.py
imports: import json
  import os
  from collections import OrderedDict
  from pathlib import Path
  from typing import Any, Dict, List, Union
  from .utils import is_dtensor_checkpoint
label_desc: Use image node_id 5 for calling the CheckpointIndexFile obj's underlying member method code with example usage: obj.append_weight_map(param_name, shard_file) without return types