class_docstr: Subset of a dataset at specified indices.
class_docstr_tok: ["Subset","of","a","dataset","at","specified","indices","."]
docstr: len
docstr_tok: ["len"]
code: def __len__(self):
      """len"""
      return len(self.indices)
  
imports: import os
  import sys
  import numpy
  from sklearn.model_selection import StratifiedKFold
  import pgl
  from pgl.utils.logger import log
label_desc: Use image node_id 3 for calling the Subset obj's underlying member method code with example usage: obj.__len__() and returns: len