code: def test_get_content_default_cm_comes_from_policy(self):
      p = policy.default.clone(
          content_manager=self._TestContentManager()
      )
      m = self._str_msg("", policy=p)
      self.assertEqual(m.get_content(), (m, (), {}))
      msg, args, kw = m.get_content("foo", bar=1, k=2)
      self.assertEqual(msg, m)
      self.assertEqual(args, ("foo",))
      self.assertEqual(kw, dict(bar=1, k=2))
  
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 5 for calling the TestEmailMessageBase obj's underlying member method code with example usage: obj.test_get_content_default_cm_comes_from_policy() without return types