code: def test_grad_negative_axis_4d(self):
      data = self.rng.random((2, 3, 4, 2)).astype(
          pytensor.config.floatX
      )
      utt.verify_grad(lambda x: sort(x, -1), [data])
      data = self.rng.random((2, 3, 4, 2)).astype(
          pytensor.config.floatX
      )
      utt.verify_grad(lambda x: sort(x, -2), [data])
      data = self.rng.random((2, 3, 4, 2)).astype(
          pytensor.config.floatX
      )
      utt.verify_grad(lambda x: sort(x, -3), [data])
      data = self.rng.random((2, 3, 4, 2)).astype(
          pytensor.config.floatX
      )
      utt.verify_grad(lambda x: sort(x, -4), [data])
  
imports: from functools import reduce
  from itertools import chain, product
  import numpy
  import pytest
  import pytensor
  from pytensor.compile.mode import Mode
  from pytensor.tensor.sort import ArgSortOp, SortOp, TopKOp, argsort, argtopk, sort, topk, topk_and_argtopk
  from pytensor.tensor.type import dmatrix, dvector, float_dtypes, integer_dtypes, lscalar, matrix, scalar, tensor, vector
  from tests import unittest_tools
label_desc: Use image node_id 12 for calling the TestSort obj's underlying member method code with example usage: obj.test_grad_negative_axis_4d() without return types