code: def check_forward(self, x_data):
      y = distributions.laplace._laplace_icdf(x_data)
      cdf = distributions.laplace._laplace_cdf(y)
      testing.assert_allclose(cdf.array, x_data)
  
imports: import unittest
  import numpy
  from chainer.backends import cuda
  from chainer import distributions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer import utils
label_desc: Use image node_id 2 for calling the TestLaplaceICDF obj's underlying member method code with example usage: obj.check_forward(x_data) without return types