code: def test_columnar_slice(self, xp, dtype):  # see cupy#2970
      if self.shape == (2, 2, 2):
          pytest.skip(
              "The length of each dimension must be the same after slicing"
          )
      a = testing.shaped_arange(self.shape, xp, dtype)
      val = self._compute_val(xp)
      xp.fill_diagonal(a[:, 1:], val=val, wrap=self.wrap)
      return a
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 3 for calling the TestFillDiagonal obj's underlying member method code with example usage: obj.test_columnar_slice(xp, dtype) and returns: a