code: def test_None(self):
      a = tensor.dmatrix()
      l = sort(a, None)
      f = theano.function([a], l)
      gv = f(self.m_val)
      gt = np.sort(self.m_val, None)
      utt.assert_allclose(gv, gt)
  
imports: from __future__ import absolute_import, print_function, division
  from itertools import product, chain
  from functools import reduce
  import unittest
  from theano.tests import unittest_tools
  import numpy
  import theano
  from theano import tensor
  from theano.tensor.sort import sort, SortOp
  from theano.tensor.sort import argsort, ArgSortOp
  from theano.tensor.sort import topk, argtopk, topk_and_argtopk, TopKOp
label_desc: Use image node_id 7 for calling the Test_sort obj's underlying member method code with example usage: obj.test_None() without return types