docs: def unwrap_or_else(self, callback: Callable[[], U]) -> Union[T, U]:
          """
          Returns the contained value or computes it from ``callback``.
  
          Args:
              callback: The the default callback.
  
          Returns:
              The contained value if the :py:class:`Option` is ``Some``,
              otherwise ``callback()``.
  
          Examples:
              >>> Some(0).unwrap_or_else(lambda: 111)
              0
              >>> NONE.unwrap_or_else(lambda: 'ha')
              'ha'
          """
          return self._val if self._is_some else callback()