code: def test_unique_axis_zeros(self):
      # issue 15559
      single_zero = np.empty(shape=(2, 0), dtype=np.int8)
      uniq, idx, inv, cnt = unique(
          single_zero,
          axis=0,
          return_index=True,
          return_inverse=True,
          return_counts=True,
      )
  
      # there's 1 element of shape (0,) along axis 0
      assert_equal(uniq.dtype, single_zero.dtype)
      assert_array_equal(uniq, np.empty(shape=(1, 0)))
      assert_array_equal(idx, np.array([0]))
      assert_array_equal(inv, np.array([[0], [0]]))
      assert_array_equal(cnt, np.array([2]))
  
      # there's 0 elements of shape (2,) along axis 1
      uniq, idx, inv, cnt = unique(
          single_zero,
          axis=1,
          return_index=True,
          return_inverse=True,
          return_counts=True,
      )
  
      assert_equal(uniq.dtype, single_zero.dtype)
      assert_array_equal(uniq, np.empty(shape=(2, 0)))
      assert_array_equal(idx, np.array([]))
      assert_array_equal(inv, np.empty((1, 0)))
      assert_array_equal(cnt, np.array([]))
  
      # test a "complicated" shape
      shape = (0, 2, 0, 3, 0, 4, 0)
      multiple_zeros = np.empty(shape=shape)
      for axis in range(len(shape)):
          expected_shape = list(shape)
          if shape[axis] == 0:
              expected_shape[axis] = 0
          else:
              expected_shape[axis] = 1
  
          assert_array_equal(
              unique(multiple_zeros, axis=axis),
              np.empty(shape=expected_shape),
          )
  
imports: import numpy
  from numpy import ediff1d, intersect1d, setxor1d, union1d, setdiff1d, unique, isin
  from numpy.exceptions import AxisError
  from numpy.testing import assert_array_equal, assert_equal, assert_raises, assert_raises_regex
  import pytest
label_desc: Use image node_id 7 for calling the TestUnique obj's underlying member method code with example usage: obj.test_unique_axis_zeros() without return types