code: def test_encoder_invalid_layer_type():
      with pytest.raises(ValueError):
          ConformerPostEncoder(20, rel_pos_type="dummy")
      with pytest.raises(ValueError):
          ConformerPostEncoder(20, pos_enc_layer_type="dummy")
      with pytest.raises(ValueError):
          ConformerPostEncoder(
              20,
              pos_enc_layer_type="abc_pos",
              selfattention_layer_type="dummy",
          )
  
imports: import pytest
  import torch
  from espnet2.slu.postencoder.conformer_postencoder import ConformerPostEncoder
label_desc: Use image node_id 2 for calling a global function with example usage: test_encoder_invalid_layer_type() without return types