code: def test_is_unique(box, value, na_like):
      obj = box([value], nan_as_null=False)
      assert obj.is_unique
  
      obj = box([value, value], nan_as_null=False)
      assert not obj.is_unique
  
      obj = box([None, value], nan_as_null=False)
      assert obj.is_unique
  
      obj = box([None, None, value], nan_as_null=False)
      assert not obj.is_unique
  
      if na_like is not None:
          obj = box([na_like, value], nan_as_null=False)
          assert obj.is_unique
  
          obj = box([na_like, na_like], nan_as_null=False)
          assert not obj.is_unique
  
          try:
              if not np.isnat(na_like):
                  # pyarrow coerces nat to null
                  obj = box([None, na_like, value], nan_as_null=False)
                  assert obj.is_unique
          except TypeError:
              pass
  
imports: import numpy
  import pandas
  import pytest
  import cudf
  from cudf import Index, MultiIndex, Series
  from cudf.core.index import CategoricalIndex, DatetimeIndex, GenericIndex, RangeIndex
  from cudf.testing._utils import assert_eq, expect_warning_if
label_desc: Use image node_id 15 for calling a global function with example usage: test_is_unique(box, value, na_like) without return types