docs: def ensure(assertion, message=None):
      """
      Checks an assertion argument for truth-ness. Will return ``True`` or
      explicitly raise ``AssertionError``. This is to deal with environments
      using ``python -O` or ``PYTHONOPTIMIZE=``.
  
      :param assertion: some value to evaluate for truth-ness
      :param message: optional message used for raising AssertionError
      """
      message = message or assertion
  
      if not assertion:
          raise AssertionError(message)
  
      return True