code: def create_look_ahead_mask(tar):
      """
      create look ahead mask for decode mask
      """
      size = tf.shape(tar)[1]
      look_ahead_mask = 1 - tf.linalg.band_part(
          tf.ones((size, size)), -1, 0
      )
      dec_target_padding_mask = create_padding_mask(tar)
      combined_mask = tf.maximum(
          dec_target_padding_mask, look_ahead_mask
      )
      return combined_mask
  
file_path: delta/delta/layers/utils_tf.py
imports: import math
  import numpy
  import tensorflow
  from tensorflow.python.util import nest
label_desc: Use image node_id 14 for calling a global function with example usage: create_look_ahead_mask(tar) and returns: combined_mask