code: def test_grad(self, shp, k_, sorted):
      ndim = len(shp)
      for axis in range(-ndim, ndim):
          if isinstance(k_, str):
              k = eval(k_.replace("n", str(shp[axis])))
          else:
              k = k_
  
          if k == 0:
              continue
  
          # make input away from undefined gradient (where some inputs are equal)
          xval = gen_unique_vector(
              reduce(int.__mul__, shp), dtype=theano.config.floatX
          ).reshape(shp)
          utt.verify_grad(
              lambda x: topk(x, k, axis=axis, sorted=sorted),
              [xval],
              eps=1e-2,
          )
  
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 10 for calling the Test_TopK obj's underlying member method code with example usage: obj.test_grad(shp, k_, sorted) without return types