class_docstr: Test the PipelineHelper class.
class_docstr_tok: ["Test","the","PipelineHelper","class","."]
code: def test_join_tuple(self):
      tup = (torch.randn(8, 5), torch.randn(8, 2))
      chunks = [tup, tup]
      j = PipelineHelper.join(chunks)
      assert isinstance(j, tuple)
      assert len(j) == 2
      a, b = j
      assert a.shape == (16, 5)
      assert b.shape == (16, 2)
  
imports: import torch
  import numpy
  import unittest
  from parlai.utils.torch import padded_tensor, argsort, PipelineHelper, neginf, IdentityLayer, trainable_parameters, total_parameters
label_desc: Use image node_id 9 for calling the TestPipelineHelper obj's underlying member method code with example usage: obj.test_join_tuple() without return types