code: def test_singular_matrix_cpu(self):
      self.check_singular_matrix(self.x)
  
imports: import unittest
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer.utils import type_check
label_desc: Use image node_id 22 for calling the DetFunctionTest obj's underlying member method code with example usage: obj.test_singular_matrix_cpu() without return types