code: def forward(self, unpooled):
      logits = self.qa_outputs(unpooled)
      # bs x seq_len x 2
      logits = logits.permute(0, 2, 1)
      # bs x 2 x seq_len x 1
      return logits
  
imports: from __future__ import annotations
  import abc
  import torch
  import torch.nn
  import transformers
  from jiant.ext.allennlp import SelfAttentiveSpanExtractor
  from jiant.shared.model_resolution import ModelArchitectures
  from jiant.tasks.core import TaskTypes
  from typing import Callable
  from typing import List
label_desc: Use image node_id 2 for calling the QAHead obj's underlying member method code with example usage: obj.forward(unpooled) and returns: logits