code: def check_single_matrix(self, x):
      x = chainer.Variable(x)
      y = self.det(x)
      if self.batched:
          self.assertEqual(y.data.ndim, 1)
      else:
          self.assertEqual(y.data.ndim, 0)
  
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 18 for calling the DetFunctionTest obj's underlying member method code with example usage: obj.check_single_matrix(x) without return types