class_docstr: Base class of a step decoder
  
  You may inherit `BaseStepDecoder` and implement the required methods.
class_docstr_tok: ["Base","class","of","a","step","decoder","You","may","inherit","`","BaseStepDecoder","`","and","implement","the","required","methods","."]
docstr: The common signature of the sequence decoder
  
  Parameters
  ----------
  data
  states
  
  Returns
  -------
  out
  new_states
docstr_tok: ["The","common","signature","of","the","sequence","decoder","Parameters","--","--","--","--","--","data","states","Returns","--","--","--","-","out","new_states"]
code: def __call__(self, data, states):
      """The common signature of the sequence decoder
  
      Parameters
      ----------
      data
      states
  
      Returns
      -------
      out
      new_states
      """
      raise NotImplementedError
  
imports: import warnings
  import mxnet
  import abc
  from mxnet.gluon import HybridBlock
  from typing import Callable, Optional
  from .layers import get_activation
label_desc: Use image node_id 4 for calling the BaseStepDecoder obj's underlying member method code with example usage: obj.__call__(data, states) without return types