code: def test_large_multi_files(self):
      large_model = _large_linear_regression()
      assert isinstance(
          large_model, onnx.model_container.ModelContainer
      )
      with tempfile.TemporaryDirectory() as temp:
          filename = os.path.join(temp, "model.onnx")
          saved_proto = large_model.save(filename, False)
          assert isinstance(saved_proto, onnx.ModelProto)
          copy = onnx.load_model(filename)
          onnx.checker.check_model(copy)
          for tensor in ext_data._get_all_tensors(copy):
              if ext_data.uses_external_data(tensor):
                  tested = 0
                  for ext in tensor.external_data:
                      if ext.key == "location":  # type: ignore[attr-defined]
                          assert os.path.exists(ext.value)
                          tested += 1
                  self.assertEqual(tested, 1)
          loaded_model = onnx.load_model(
              filename, load_external_data=True
          )
          onnx.checker.check_model(loaded_model)
  
file_path: onnx/onnx/test/model_container_test.py
imports: import os
  import tempfile
  import unittest
  import numpy
  import onnx
  import onnx.external_data_helper
  import onnx.helper
  import onnx.model_container
  import onnx.numpy_helper
label_desc: Use image node_id 3 for calling the TestLargeOnnx obj's underlying member method code with example usage: obj.test_large_multi_files() without return types