code: def test_init(self):
      decoder = ParallelSARDecoder(self.dict_cfg)
      self.assertIsInstance(decoder.rnn_decoder, torch.nn.LSTM)
      decoder = ParallelSARDecoder(
          self.dict_cfg, dec_gru=True, pred_concat=True
      )
      self.assertIsInstance(decoder.rnn_decoder, torch.nn.GRU)
  
file_path: mmocr/tests/test_models/test_textrecog/test_decoders/test_sar_decoder.py
imports: from unittest import TestCase
  import torch
  from mmengine.structures import LabelData
  from mmocr.models.textrecog.decoders import ParallelSARDecoder, SequentialSARDecoder
  from mmocr.structures import TextRecogDataSample
label_desc: Use image node_id 2 for calling the TestParallelSARDecoder obj's underlying member method code with example usage: obj.test_init() without return types