docstr: test for GH issue 94606
code: def get_payload_surrogate_as_gh_94606(self, msg, expected):
      """test for GH issue 94606"""
      m = self._str_msg(msg)
      payload = m.get_payload(decode=True)
      self.assertEqual(expected, payload)
  
imports: import unittest
  import textwrap
  from email import policy, message_from_string
  from email.message import EmailMessage, MIMEPart
  from test.test_email import TestEmailBase, parameterize
label_desc: Use image node_id 20 for calling the TestEmailMessageBase obj's underlying member method code with example usage: obj.get_payload_surrogate_as_gh_94606(msg, expected) without return types