code: def __init__(self, start: int, total: int, step: Optional[int]):
      self.step = step
      self.total = total
      self.start = start
      self.i = None
  
imports: import signal
  import typing
  from typing import Optional, Tuple, Any, Collection
  from labml import tracker, logger, experiment, monit
  from labml.configs import BaseConfigs, meta_config, option
  from labml.internal.monitor import Loop
  from labml.logger import Text
label_desc: Use image node_id 1 to create a new TrainingLoopIterator object from inherited base classes: Collection with example: obj = TrainingLoopIterator(start, total, step)