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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_same_segment( query_segment, memory_segment=None, dtype=tf.float32):
 """Bias for attention where attention between segments is disallowed. Args: dtype: a tf.dtype Returns: """

  memory_segment = rename_length_to_memory_length(
      memory_segment or query_segment)
  return mtf.cast(mtf.not_equal(query_segment, memory_segment), dtype) * -1e9