code: def testVocabSize(self):
      encoder = music_encoders.TextChordsEncoder(steps_per_quarter=1)
      self.assertEqual(51, encoder.vocab_size)
  
imports: import tempfile
  from magenta.models.score2perf import music_encoders
  import note_seq
  from note_seq import testing_lib
  import tensorflow.compat.v1
label_desc: Use image node_id 3 for calling the TextChordsEncoderTest obj's underlying member method code with example usage: obj.testVocabSize() without return types