code: def _get_unused_byte(size_list: List[int], chunk_size: int) -> int:
      """_get_unused_byte
  
      Get unused byte for a certain chunk size.
  
      Args:
          size_list (List[int]): the size list of parameters.
          chunk_size (int): the chunk size.
  
      Returns:
          int: the unused byte.
      """
      acc = 0
      left = 0
      for s in size_list:
          if s > left:
              acc += left
              left = chunk_size
          left -= s
      return left + acc
  
file_path: ColossalAI/colossalai/zero/gemini/chunk/search_utils.py
imports: import math
  from typing import Dict, List, Optional, Tuple
  import numpy
  import torch.distributed
  import torch.nn
  from torch.distributed import ProcessGroup
  from colossalai.tensor import ColoParameter
  from colossalai.utils import is_ddp_ignored
  from colossalai.zero.gemini.memory_tracer import MemStats, OrderedParamGenerator
label_desc: Use image node_id 2 for calling a global function with example usage: _get_unused_byte(size_list, chunk_size) and returns: unknown