code: def export_default_mask_ratio() -> None:
      seed = np.int64(0)
      node = onnx.helper.make_node(
          "Dropout", inputs=["x", "r"], outputs=["y", "z"], seed=seed
      )
  
      r = np.float32(0.1)
      x = np.random.randn(3, 4, 5).astype(np.float32)
      y, z = dropout(x, r, return_mask=True)
      expect(
          node,
          inputs=[x, r],
          outputs=[y, z],
          name="test_dropout_default_mask_ratio",
      )
  
file_path: onnx/onnx/backend/test/case/node/dropout.py
imports: import numpy
  import onnx
  from onnx import helper
  from onnx.backend.test.case.base import Base
  from onnx.backend.test.case.node import expect
label_desc: Use image node_id 4 for calling the Dropout obj's underlying member method code with example usage: obj.export_default_mask_ratio() without return types