class_docstr: Overrides BaseDecoder to include rnn inputs in the output.
class_docstr_tok: ["Overrides","BaseDecoder","to","include","rnn","inputs","in","the","output","."]
code: def output_size(self):
      return Seq2SeqLstmDecoderOutput(
          rnn_input=self._input_shape,
          rnn_output=self._rnn_output_size(),
          sample_id=self._helper.sample_ids_shape,
      )
  
imports: import collections
  from magenta.contrib import rnn
  from magenta.contrib import seq2seq
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling the Seq2SeqLstmDecoder obj's underlying member method code with example usage: obj.output_size() and returns: Seq2SeqLstmDecoderOutput