Legacy access to editor role.

        DEPRECATED:  use ``policy["roles/editors"]`` instead.

def editors(self):
        """Legacy access to editor role.

        DEPRECATED:  use ``policy["roles/editors"]`` instead."""
        result = set()
        for role in self._EDITOR_ROLES:
            for member in self._bindings.get(role, ()):
                result.add(member)
        return frozenset(result)