class_docstr: A manager class to manipulate the tensors in chunks.
  
  Args:
      chunk_configuration (Dict[int, Dict]): the configuration dictionary of this chunk manager.
      init_device (torch.device): optional, the device on which the chunk is initialized. The default is None.
docstr: Register a chunk group.
docstr_tok: ["Register","a","chunk","group","."]
code: def __get_chunk_group(self, group_name: str) -> Deque[Chunk]:
      """Register a chunk group."""
      if group_name not in self.chunk_groups:
          self.chunk_groups[group_name] = deque()
      return self.chunk_groups[group_name]
  
imports: from collections import deque
  from typing import Deque, Dict, Iterable, List, Optional, Set, Tuple
  import torch
  import torch.distributed
  from torch.distributed import ProcessGroup
  from colossalai.utils import free_storage, get_current_device
  from .chunk import Chunk, ChunkFullError, TensorState
label_desc: Use image node_id 16 for calling the ChunkManager obj's underlying member method code with example usage: obj.__get_chunk_group(group_name) and returns: self