code: def test_bom_handling(self, string, input_encoding, expected):
      with self.test_session():
          output = string_ops.unicode_transcode(
              string,
              input_encoding=input_encoding,
              output_encoding="UTF-8",
          )
          self.assertAllEqual(output, expected)
  
imports: from absl.testing import parameterized
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 19 for calling the UnicodeTranscodeOpTest obj's underlying member method code with example usage: obj.test_bom_handling(string, input_encoding, expected) without return types