code: def __len__(self):
      return len(self.df)
  
imports: import argparse
  import os
  import albumentations
  import numpy
  import pandas
  import timm
  import torch
  import torch.nn
  from sklearn import metrics, model_selection
  from tez import Tez, TezConfig
  from tez.callbacks import EarlyStopping
  from tez.utils import seed_everything
label_desc: Use image node_id 2 for calling the DigitRecognizerDataset obj's underlying member method code with example usage: obj.__len__() and returns: len