class_docstr: ProcessGroupManager is used to manage the process groups in the cluster.
  
  There are some terms used in this class:
      - pg: the short name for process group
      - pg_name: the name of the process group
      - pg_size: the world size of the process group
      - rank: the rank of the current process in the process group
      - world_size: the total number of processes in the process group
code: def __init__(self):
      self.pg_store = dict()
  
file_path: colossalai/colossalai/cluster/process_group_manager.py
imports: from typing import List
  import torch.distributed
  from torch.distributed import ProcessGroup
label_desc: Use image node_id 1 to create a new ProcessGroupManager object  with example: obj = ProcessGroupManager()