text: from typing import Union
  import pytest
  from outgoing_mailgun import yesno
  
  
  @pytest.mark.parametrize(
      "b,out",
      [
          (True, "yes"),
          (False, "no"),
          ("htmlonly", "htmlonly"),
      ],
  )
  def test_yesno(b: Union[bool, str], out: str) -> None:
      assert yesno(b) == out
  