code: def export_default_axis() -> None:
      X = np.random.randn(2, 3, 4, 5).astype(np.float32)
  
      # Default axis in LayerNormalization is -1.
      normalized_shape = calculate_normalized_shape(X.shape, -1)
      W = np.random.randn(*normalized_shape).astype(np.float32)
      B = np.random.randn(*normalized_shape).astype(np.float32)
      # Axis is default to -1 in the reference implementation.
      Y, mean, inv_std_dev = _layer_normalization(X, W, B)
  
      # Not specifying axis attribute means -1.
      node = onnx.helper.make_node(
          "LayerNormalization",
          inputs=["X", "W", "B"],
          outputs=["Y", "Mean", "InvStdDev"],
      )
  
      expect(
          node,
          inputs=[X, W, B],
          outputs=[Y, mean, inv_std_dev],
          name="test_layer_normalization_default_axis",
      )
  
file_path: onnx/onnx/backend/test/case/node/layernormalization.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 2 for calling the LayerNormalization obj's underlying member method code with example usage: obj.export_default_axis() without return types