code: def test_pad(self):
      padded_batch = self.field.pad(self.unpadded_batch)
      expected_padded_batch_np = np.array(self.expected_padded_batch)
      padded_batch_np = np.array(padded_batch)
  
      self.assertEqual(
          padded_batch_np.shape, expected_padded_batch_np.shape
      )
      for i in range(len(self.expected_padded_batch)):
          for j in range(len(self.expected_padded_batch[i])):
              for k in range(len(self.expected_padded_batch[i][j])):
                  self.assertEqual(
                      padded_batch[i][j][k],
                      self.expected_padded_batch[i][j][k],
                  )
  
imports: import unittest
  import numpy
  from pytext.fields.contextual_token_embedding_field import ContextualTokenEmbeddingField
label_desc: Use image node_id 2 for calling the ContextualTokenEmbeddingFieldTest obj's underlying member method code with example usage: obj.test_pad() without return types