code: def test_dbcs_keep_buffer(self):
      decoder = codecs.getincrementaldecoder("cp949")()
      self.assertEqual(decoder.decode(b"\xc6\xc4\xc0"), "\ud30c")
      self.assertRaises(UnicodeDecodeError, decoder.decode, b"", True)
      self.assertEqual(decoder.decode(b"\xcc"), "\uc774")
  
      self.assertEqual(decoder.decode(b"\xc6\xc4\xc0"), "\ud30c")
      self.assertRaises(
          UnicodeDecodeError, decoder.decode, b"\xcc\xbd", True
      )
      self.assertEqual(decoder.decode(b"\xcc"), "\uc774")
  
imports: import _multibytecodec
  import codecs
  import io
  import sys
  import textwrap
  import unittest
  from test import support
  from test.support import os_helper
  from test.support.os_helper import TESTFN
label_desc: Use image node_id 2 for calling the Test_IncrementalDecoder obj's underlying member method code with example usage: obj.test_dbcs_keep_buffer() without return types