code: def test_unfold_long_sequences(self):
      # Let's just say [PAD] is 0, [CLS] is xxx1, and [SEP] is xxx2
      # We assume embeddings are 1-dim and are the same as indices
      embeddings = torch.LongTensor(
          [
              [1001, 101, 102, 103, 104, 1002],
              [1011, 105, 106, 107, 108, 1012],
              [1021, 109, 1022, 0, 0, 0],
              [2001, 201, 202, 203, 204, 2002],
              [2011, 205, 206, 207, 208, 2012],
              [0, 0, 0, 0, 0, 0],
              [3001, 301, 3002, 0, 0, 0],
              [0, 0, 0, 0, 0, 0],
              [0, 0, 0, 0, 0, 0],
          ]
      ).unsqueeze(-1)
      mask = (embeddings > 0).long()
  
      unfolded_embeddings = torch.LongTensor(
          [
              [1001, 101, 102, 103, 104, 105, 106, 107, 108, 109, 1022],
              [2001, 201, 202, 203, 204, 205, 206, 207, 208, 2012, 0],
              [3001, 301, 3002, 0, 0, 0, 0, 0, 0, 0, 0],
          ]
      ).unsqueeze(-1)
  
      token_embedder = PretrainedTransformerEmbedder(
          "bert-base-uncased", max_length=6
      )
  
      unfolded_embeddings_out = token_embedder._unfold_long_sequences(
          embeddings, mask, unfolded_embeddings.size(0), 15
      )
      assert (unfolded_embeddings_out == unfolded_embeddings).all()
  
imports: import math
  import pytest
  import torch
  from allennlp.common import Params, cached_transformers
  from allennlp.common.testing import AllenNlpTestCase, requires_gpu
  from allennlp.data import Vocabulary
  from allennlp.data.batch import Batch
  from allennlp.data.fields import TextField
  from allennlp.data.instance import Instance
  from allennlp.data.token_indexers import PretrainedTransformerIndexer
  from allennlp.data.tokenizers import PretrainedTransformerTokenizer
  from allennlp.modules.text_field_embedders import BasicTextFieldEmbedder
  from allennlp.modules.token_embedders import PretrainedTransformerEmbedder
label_desc: Use image node_id 9 for calling the TestPretrainedTransformerEmbedder obj's underlying member method code with example usage: obj.test_unfold_long_sequences() without return types