code: def export_beta() -> None:
      node = onnx.helper.make_node(
          "Gemm", inputs=["a", "b", "c"], outputs=["y"], beta=0.5
      )
      a = np.random.ranf([2, 7]).astype(np.float32)
      b = np.random.ranf([7, 4]).astype(np.float32)
      c = np.random.ranf([1, 4]).astype(np.float32)
      y = gemm_reference_implementation(a, b, c, beta=0.5)
      expect(node, inputs=[a, b, c], outputs=[y], name="test_gemm_beta")
  
file_path: onnx/onnx/backend/test/case/node/gemm.py
imports: from typing import Optional
  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 10 for calling the Gemm obj's underlying member method code with example usage: obj.export_beta() without return types