code: def add_length(x, y=None):
      x["length"] = tf.shape(x["tokens"])[0]
      if y is not None:
          return x, y
      return x
  
file_path: finetune/finetune/util/input_utils.py
imports: import math
  import tensorflow
  from finetune.util.timing import ProgressBar
label_desc: Use image node_id 4 for calling a global function with example usage: add_length(x, y) and returns: x, x,  y