code: def d_output(self):
      return self.d_input * self.expand
  
imports: import torch
  import torch.nn.functional
  from einops import rearrange, reduce, repeat
  from torch import nn
  from espnet2.asr.state_spaces.base import SequenceModule
  from espnet2.asr.state_spaces.components import LinearActivation
label_desc: Use image node_id 4 for calling the DownLinearPool obj's underlying member method code with example usage: obj.d_output() and returns: unknown