code: def testStringSplitEmptyDelimiter(self):
      strings = [
          "hello",
          "hola",
          b"\xF0\x9F\x98\x8E",
      ]  # Last string is U+1F60E
  
      with self.cached_session():
          tokens = string_ops.string_split(strings, delimiter="")
          indices, values, shape = self.evaluate(tokens)
          self.assertAllEqual(
              indices,
              [
                  [0, 0],
                  [0, 1],
                  [0, 2],
                  [0, 3],
                  [0, 4],
                  [1, 0],
                  [1, 1],
                  [1, 2],
                  [1, 3],
                  [2, 0],
                  [2, 1],
                  [2, 2],
                  [2, 3],
              ],
          )
          expected = np.array(
              [
                  "h",
                  "e",
                  "l",
                  "l",
                  "o",
                  "h",
                  "o",
                  "l",
                  "a",
                  b"\xf0",
                  b"\x9f",
                  b"\x98",
                  b"\x8e",
              ],
              dtype="|S1",
          )
          self.assertAllEqual(values.tolist(), expected)
          self.assertAllEqual(shape, [3, 5])
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.ops.ragged import ragged_string_ops
  from tensorflow.python.platform import test
  from tensorflow.python.util import compat
label_desc: Use image node_id 2 for calling the StringSplitOpTest obj's underlying member method code with example usage: obj.testStringSplitEmptyDelimiter() without return types