code: def test_average_sum_last_k(self):
      pool_fn = poolers.AverageSumLastK(self.k).to(self.device)
      out = pool_fn(self.encoded_layers, self.pad_mask)
  
      assert (
          torch.Size([self.batch_size, self.embedding_size])
          == out.shape
      )
  
file_path: mmf/tests/modules/test_poolers.py
imports: import unittest
  import mmf.modules.poolers
  import torch
  from mmf.utils.general import get_current_device
label_desc: Use image node_id 4 for calling the TestModulePoolers obj's underlying member method code with example usage: obj.test_average_sum_last_k() without return types