code: def _create_posdef_matrix(self, xp, shape, dtype):
      n = shape[-1]
      a = testing.shaped_random(shape, xp, dtype, scale=1)
      a = a @ a.swapaxes(-2, -1).conjugate()
      a = a + n * xp.eye(n)
      return a
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
  import cupyx
  from cupyx import cusolver, lapack
label_desc: Use image node_id 3 for calling the TestPosv obj's underlying member method code with example usage: obj._create_posdef_matrix(xp, shape, dtype) and returns: a