code: def default_state(self, *batch_shape, device=None):
      state = torch.zeros(
          batch_shape + (self.d_output, self.stride), device=device
      )  # (batch, h, s)
      state = list(torch.unbind(state, dim=-1))  # List of (..., H)
      return state
  
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 UpPool obj's underlying member method code with example usage: obj.default_state() and returns: state