code: def test_unique_empty_return_all(self, xp, dtype):
      a = xp.empty((3, 0, 2), dtype)
      return xp.unique(
          a,
          return_index=True,
          return_inverse=True,
          return_counts=True,
          axis=2,
      )
  
imports: import unittest
  import pytest
  import numpy
  import cupy
  from cupy import testing
label_desc: Use image node_id 14 for calling the TestUnique obj's underlying member method code with example usage: obj.test_unique_empty_return_all(xp, dtype) and returns: xp