class_docstr: Abstract sequence model class.
  
  All models must adhere to this interface
  
  A SequenceModule is generally a model that transforms an input of shape
  (n_batch, l_sequence, d_model) to (n_batch, l_sequence, d_output)
  
  REQUIRED methods and attributes
  forward, d_model, d_output: controls standard forward pass,
  a sequence-to-sequence transformation
  __init__ should also satisfy the following interface;
  see SequenceIdentity for an example
      def __init__(self, d_model, transposed=False, **kwargs)
  
  OPTIONAL methods
  default_state, step: allows stepping the model recurrently with a hidden state
  state_to_tensor, d_state: allows decoding from hidden state
class_docstr_tok: ["Abstract","sequence","model","class",".","All","models","must","adhere","to","this","interface","A","SequenceModule","is","generally","a","model","that","transforms","an","input","of","shape","(","n_batch",",","l_sequence",",","d_model",")","to","(","n_batch",",","l_sequence",",","d_output",")","REQUIRED","methods","and","attributes","forward",",","d_model",",","d_output",":","controls","standard","forward","pass",",","a","sequence-to-sequence","transformation","__init__","should","also","satisfy","the","following","interface",";","see","SequenceIdentity","for","an","example","def","__init__","(","self",",","d_model",",","transposed=False",",","*","*","kwargs",")","OPTIONAL","methods","default_state",",","step",":","allows","stepping","the","model","recurrently","with","a","hidden","state","state_to_tensor",",","d_state",":","allows","decoding","from","hidden","state"]
docstr: Create initial state for a batch of inputs.
docstr_tok: ["Create","initial","state","for","a","batch","of","inputs","."]
code: def default_state(self, *batch_shape, device=None):
      """Create initial state for a batch of inputs."""
      return None
  
file_path: espnet/espnet2/asr/state_spaces/base.py
imports: import functools
  from torch import nn
label_desc: Use image node_id 8 for calling the SequenceModule obj's underlying member method code with example usage: obj.default_state() and returns: None