code: def check_forward(self, inputs_data, atol=1e-4, rtol=1e-5):
      out = self.op(*[chainer.Variable(x) for x in inputs_data])
      testing.assert_allclose(self.forward_answer, out.data, atol, rtol)
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer.functions.math import einsum
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer import utils
label_desc: Use image node_id 4 for calling the TestEinSum obj's underlying member method code with example usage: obj.check_forward(inputs_data, atol, rtol) without return types