code: def test_onnx_export(self):
      model = get_pretrained_bert_345m_uncased_model()
      assert model
      with tempfile.TemporaryDirectory() as tmpdir:
          # Generate filename in the temporary directory.
          # Test export.
          model.export(os.path.join(".", "megatron.onnx"))
  
file_path: NeMo/tests/collections/nlp/test_megatron.py
imports: import os
  import tempfile
  import onnx
  import pytest
  import torch
  from omegaconf import OmegaConf
  import nemo.collections.nlp
  from nemo.core.classes import typecheck
label_desc: Use image node_id 3 for calling the TestMegatron obj's underlying member method code with example usage: obj.test_onnx_export() without return types