code: def export_tril_square_neg() -> None:
      node = onnx.helper.make_node(
          "Trilu",
          inputs=["x", "k"],
          outputs=["y"],
          upper=0,
      )
  
      x = np.random.randint(10, size=(2, 3, 3)).astype(np.int64)
      k = np.array(-1).astype(np.int64)
      # X:
      # [[[0, 4, 3],
      #   [2, 0, 9],
      #   [8, 2, 5]],
      #
      #  [[2, 7, 2],
      #   [2, 6, 0],
      #   [2, 6, 5]]]
      # expect result:
      # [[[0, 0, 0],
      #   [2, 0, 0],
      #   [8, 2, 0]],
      #
      #  [[0, 0, 0],
      #   [2, 0, 0],
      #   [2, 6, 0]]]
      y = tril_reference_implementation(x, int(k))
      expect(
          node, inputs=[x, k], outputs=[y], name="test_tril_square_neg"
      )
  
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 16 for calling the Trilu obj's underlying member method code with example usage: obj.export_tril_square_neg() without return types