code: def __init__(self) -> None:
      self.start_time: Optional[float] = None
      self.duration: float = 0.0
  
file_path: colossalai/examples/language/llama2/performance_evaluator.py
imports: from time import time
  from typing import Optional
  import torch
  import torch.distributed
  from torch import Tensor
  import colossalai.utils.device
  from colossalai.cluster import DistCoordinator
  from colossalai.utils.device import get_current_device
label_desc: Use image node_id 1 to create a new Timer object  with example: obj = Timer()