code: def test_issue5640(self):
      encoder = codecs.getincrementalencoder("shift-jis")(
          "backslashreplace"
      )
      self.assertEqual(encoder.encode("\xff"), b"\\xff")
      self.assertEqual(encoder.encode("\n"), b"\n")
  
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 9 for calling the Test_IncrementalEncoder obj's underlying member method code with example usage: obj.test_issue5640() without return types