code: def __len__(self):
      return math.ceil(len(self.x) / self.batch_size)
  
imports: import math
  import os
  from collections import Counter
  import numpy
  from keras.utils import Sequence, get_file
label_desc: Use image node_id 3 for calling the NERSequence obj's underlying member method code with example usage: obj.__len__() and returns: math