def choices(self):
        """
        When it's time to get the choices, if it was a lazy then figure it out
        now and memoize the result.
        """
        if isinstance(self._choices, Promise):
            self._choices = list(self._choices)
        return self._choices
When it's time to get the choices, if it was a lazy then figure it out
        now and memoize the result.