def registered(self, ref=None):
        """ get an actor by it's ref """
        print(type(core.getcurrent()))
        if ref is None:
            try:
                ref = core.getcurrent().ref
            except AttributeError:
                return []


        print(ref)
        print(self._by_ref)

        if self._by_ref not in ref:
            return []
        print(self._by_ref[ref])
        return sorted(self._by_ref[ref])
dataset/ETHPy150Open benoitc/flower/flower/registry.py/Registry.registered/swapped operands of `not in`