code: def test_callback_chained(self) -> None:
      awaitable = AwaitableInstance()
      awaitable.callbacks.append(lambda ret: 2 * ret)
      awaitable.callbacks.append(lambda ret: ret**2)
      self.assertTrue(
          torch.allclose(
              awaitable.wait(), torch.FloatTensor([4.0, 16.0, 36.0])
          )
      )
  
file_path: torchrec/torchrec/distributed/tests/test_awaitable.py
imports: import unittest
  import torch
  from torchrec.distributed.types import Awaitable
label_desc: Use image node_id 2 for calling the AwaitableTests obj's underlying member method code with example usage: obj.test_callback_chained() without return types