code: def test_invalid_format_non_exist(self):
      non_exist_filename = self.model_path_pb.replace(
          ".pb", "_non_exist.pb"
      )
      with pytest.raises(ValueError) as e:
          converter.convert(non_exist_filename, source="tensorflow")
      e.match(r"Input model .* does not exist")
  
imports: import numpy
  import os
  import six
  import pytest
  import shutil
  import tempfile
  import coremltools
  import coremltools.converters
  from coremltools._deps import _IS_MACOS
  import coremltools.proto.FeatureTypes_pb2
  from coremltools import TensorType, ImageType, RangeDim, EnumeratedShapes
  from coremltools.converters.mil.testing_utils import random_gen
  from coremltools.converters.mil.frontend.tensorflow.converter import TFConverter
  from coremltools.converters.mil.frontend.tensorflow.test.testing_utils import frontend, make_tf_graph, run_compare_tf, get_tf_keras_io_names
label_desc: Use image node_id 14 for calling the TestTf1ModelFormats obj's underlying member method code with example usage: obj.test_invalid_format_non_exist() without return types