class_docstr: Dataset for progressive training.
code: def __len__(self):
      return len(self.internal_dataset)
  
file_path: nebuly/optimization/forward_forward/forward_forward/utils/utils.py
imports: from collections import Generator
  import torch.utils.data
label_desc: Use image node_id 3 for calling the ProgressiveTrainingDataset obj's underlying member method code with example usage: obj.__len__() and returns: len