class_docstr: Tests HierarchicalRNNEncoder
      
code: def test_depack(self):
      hparams = {
          "encoder_major_type": "BidirectionalRNNEncoder",
          "encoder_major_hparams": {
              "rnn_cell_fw": {
                  "type": "LSTMCell",
                  "kwargs": {"num_units": 100},
              }
          },
      }
      encoder = HierarchicalRNNEncoder(hparams=hparams)
  
      batch_size = 16
      max_major_time = 8
      max_minor_time = 6
      dim = 10
      inputs = tf.random_uniform(
          [batch_size, max_major_time, max_minor_time, dim],
          maxval=1,
          minval=-1,
          dtype=tf.float32,
      )
  
      _, _ = encoder(inputs)
  
      self.assertEqual(
          encoder.states_minor_before_medium.h.shape[1],
          encoder.states_minor_after_medium.shape[1],
      )
  
file_path: texar/tests/modules/encoders/hierarchical_encoders_test.py
imports: import tensorflow
  from texar.tf.modules.encoders.hierarchical_encoders import HierarchicalRNNEncoder
label_desc: Use image node_id 4 for calling the HierarchicalRNNEncoderTest obj's underlying member method code with example usage: obj.test_depack() without return types