code: def load_model(file_path):
      
      if not path.exists(file_path):
          raise FileNotFoundError("{0} was not found.".format(file_path))
      model = onnx_proto.ModelProto()
      with open(file_path, 'rb') as f:
          model.ParseFromString(f.read())
      return model
docs: Loads an ONNX model to a ProtoBuf object.
  
      :param file_path: ONNX file (full file name)
      :return: ONNX model.
  
      Example:
  
      ::
  
          from onnxmltools.utils import load_model
          onnx_model = load_model("SqueezeNet.onnx")