code: def scalar(self):
      a = chainer.Variable(np.array(7, dtype=np.float32))
      b = chainer.Variable(np.array(2, dtype=np.float32))
      return (a, b)
  
imports: import chainer
  import chainer.functions
  from chainer import testing
  from chainer.testing import attr
  import numpy
  import pytest
  from onnx_chainer.testing import input_generator
  from onnx_chainer_tests.helper import ONNXModelTest
label_desc: Use image node_id 5 for calling the TestBinaryMathOperators obj's underlying member method code with example usage: obj.scalar() and returns: a,  b