module if you need to store extra state. This function is called
      when building the module's state_dict().
  Note that extra state should be picklable to ensure working
  serialization of the state_dict. We only provide provide
  backwards compatibility guarantees for serializing Tensors;
  other objects may break backwards compatibility if their
  serialized pickled form changes.

  Returns:
     Any extra state to store in the module's state_dict

  Return type:
     object

get_parameter(target)
  Returns the parameter given by "target" if it exists, otherwise
  throws an error.

  See the docstring for "get_submodule" for a more detailed
  explanation of this method's functionality as well as how to
  correctly specify "target".

  Parameters:
     **target** (*str*) -- The fully-qualified string name of the
     Parameter to look for. (See "get_submodule" for how to
     specify a fully-qualified string.)
