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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def attention_mask_ignore_padding(inputs, dtype=tf.float32):
 """Bias for encoder-decoder attention. Args: dtype: a tf.dtype Returns: """

  inputs = rename_length_to_memory_length(inputs)
  return mtf.cast(mtf.equal(inputs, 0), dtype) * -1e9