code: def testSimpleString(self):
      self._testSimpleHelper(
          dtypes.string,
          [
              ([], []),
              (["hello"], ["hello"]),
              (["hello", "hello", "hello"], ["hello"]),
              (["hello", "world"], ["hello", "world"]),
              (
                  ["foo", "bar", "baz", "baz", "bar", "foo"],
                  ["foo", "bar", "baz"],
              ),
          ],
      )
  
imports: from absl.testing import parameterized
  from tensorflow.python.data.kernel_tests import checkpoint_test_base
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import dtypes
  from tensorflow.python.platform import test
  from tensorflow.python.util import compat
label_desc: Use image node_id 3 for calling the UniqueTest obj's underlying member method code with example usage: obj.testSimpleString() without return types