code: def check_forward(self, x_data):
      x = chainer.Variable(x_data)
      y = self.link(x)
      self.assertEqual(y.data.dtype, numpy.float32)
  
      y_expect = self.x.copy()
      for i in numpy.ndindex(self.x.shape):
          if self.x[i] < 0:
              y_expect[i] *= self.W
  
      testing.assert_allclose(y_expect, y.data)
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import gradient_check
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import condition
label_desc: Use image node_id 2 for calling the TestPReLUSingle obj's underlying member method code with example usage: obj.check_forward(x_data) without return types