class_docstr: Simple callback that logs how long each epoch takes, in seconds, to a pytorch lightning log
      
code: def on_train_epoch_start(self, trainer, pl_module):
      self.epoch_start = time.time()
  
imports: import time
  from pytorch_lightning.callbacks import Callback
  from pytorch_lightning.utilities import rank_zero_only
label_desc: Use image node_id 1 for calling the LogEpochTimeCallback obj's underlying member method code with example usage: obj.on_train_epoch_start(trainer, pl_module) without return types