当Stack Navigator嵌套在另一个Stack Navigator中时，如何返回？而不显示两个标题？

const OuterStackNavigator = createStackNavigator({
  InnerStack: {
    screen: InnerStackNavigator,
    navigationOptions: {
      header: null, // 隐藏外层标题栏
    },
  },
  // 其他屏幕
});

const InnerStackNavigator = createStackNavigator({
  Screen1: {
    screen: Screen1,
    navigationOptions: ({ navigation }) => ({
      headerLeft: (
        <TouchableOpacity onPress={() => navigation.goBack()}>
          <Text>返回</Text>
        </TouchableOpacity>
      ),
    }),
  },
  // 其他屏幕
});