code: def test_send_smtp_with_multibyte_content(self, mock_send_mime):
      email.send_email_smtp("to", "subject", "🔥", mime_charset="utf-8")
      assert mock_send_mime.called
      _, call_args = mock_send_mime.call_args
      msg = call_args["mime_msg"]
      mimetext = MIMEText("🔥", "mixed", "utf-8")
      assert (
          mimetext.get_payload() == msg.get_payload()[0].get_payload()
      )
  
imports: from __future__ import annotations
  import os
  from email.mime.application import MIMEApplication
  from email.mime.multipart import MIMEMultipart
  from email.mime.text import MIMEText
  from smtplib import SMTPServerDisconnected
  from unittest import mock
  import pytest
  from airflow.configuration import conf
  from airflow.utils import email
  from tests.test_utils.config import conf_vars
label_desc: Use image node_id 2 for calling the TestEmailSmtp obj's underlying member method code with example usage: obj.test_send_smtp_with_multibyte_content(mock_send_mime) without return types