class_docstr: Tests the `AttentionDecoder` class.
    
class_docstr_tok: ["Tests","the","`","AttentionDecoder","`","class","."]
code: def test_attention_scores(self):
      decoder_output_ = self.test_with_fixed_inputs()
      np.testing.assert_array_equal(
          decoder_output_.attention_scores.shape,
          [self.sequence_length, self.batch_size, self.input_seq_len],
      )
  
      # Make sure the attention scores sum to 1 for each step
      scores_sum = np.sum(decoder_output_.attention_scores, axis=2)
      np.testing.assert_array_almost_equal(
          scores_sum, np.ones([self.sequence_length, self.batch_size])
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import tensorflow
  import numpy
  from seq2seq.decoders import BasicDecoder, AttentionDecoder, AttentionLayerDot
  from seq2seq.decoders import beam_search_decoder
  from seq2seq.inference import beam_search
  from seq2seq.contrib.seq2seq import helper
label_desc: Use image node_id 3 for calling the AttentionDecoderTest obj's underlying member method code with example usage: obj.test_attention_scores() without return types