code: def export_identity_opt() -> None:
      ten_in_tp = onnx.helper.make_tensor_type_proto(
          onnx.TensorProto.FLOAT, shape=[5]
      )
      seq_in_tp = onnx.helper.make_sequence_type_proto(ten_in_tp)
      opt_in_tp = onnx.helper.make_optional_type_proto(seq_in_tp)
  
      identity_node = onnx.helper.make_node(
          "Identity", inputs=["opt_in"], outputs=["opt_out"]
      )
  
      x = [np.array([1, 2, 3, 4, 5]).astype(np.float32)]
  
      expect(
          identity_node,
          inputs=[x],
          outputs=[x],
          name="test_identity_opt",
          opset_imports=[onnx.helper.make_opsetid("", 16)],
          input_type_protos=[opt_in_tp],
          output_type_protos=[opt_in_tp],
      )
  
file_path: onnx/onnx/backend/test/case/node/identity.py
imports: import numpy
  import onnx
  from onnx.backend.test.case.base import Base
  from onnx.backend.test.case.node import expect
label_desc: Use image node_id 3 for calling the Identity obj's underlying member method code with example usage: obj.export_identity_opt() without return types