code: def __len__(self):
      return len(self.features)
  
imports: import os
  import tempfile
  import numpy
  import pandas
  import scipy.sparse
  from sklearn.model_selection import train_test_split
  from sklearn.preprocessing import MinMaxScaler
  import torch.utils.data
  from bigdl.dllib.utils.file_utils import is_local_path
  from bigdl.orca.data.file import get_remote_dir_to_local, get_remote_file_to_local
label_desc: Use image node_id 5 for calling the NCFData obj's underlying member method code with example usage: obj.__len__() and returns: len