class_docstr: TODO: implement forward_attention
  TODO: location sensitive attention
  TODO: implement attention windowing 
class_docstr_tok: ["TODO",":","implement","forward_attention","TODO",":","location","sensitive","attention","TODO",":","implement","attention","windowing"]
docstr: ignore sequence paddings 
docstr_tok: ["ignore","sequence","paddings"]
code: def apply_score_masking(
      self, score, mask
  ):  # pylint: disable=no-self-use
      """ignore sequence paddings"""
      padding_mask = tf.expand_dims(math_ops.logical_not(mask), 2)
      # Bias so padding positions do not contribute to attention distribution.
      score -= 1.0e9 * math_ops.cast(padding_mask, dtype=tf.float32)
      return score
  
imports: import tensorflow
  from tensorflow import keras
  from tensorflow.python.ops import math_ops
label_desc: Use image node_id 6 for calling the Attention obj's underlying member method code with example usage: obj.apply_score_masking(score, mask) and returns: score