code: def test_diagflat_from_scalar_with_k0(self, xp):
      return xp.diagflat(3, 0)
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 16 for calling the TestMatrix obj's underlying member method code with example usage: obj.test_diagflat_from_scalar_with_k0(xp) and returns: xp