class_docstr: Used by split_dataset
code: def __len__(self):
      return len(self.keys)
  
file_path: dowhy/dowhy/causal_prediction/dataloaders/misc.py
imports: import hashlib
  from collections import Counter
  import numpy
  import torch
label_desc: Use image node_id 3 for calling the _SplitDataset obj's underlying member method code with example usage: obj.__len__() and returns: len