What is the working of AddSelectors() and SelectPartnerState() ?

[Kundan-pseudo]

// test file

import { Button } from '@mui/material';
import React from 'react'
import { useDispatch, useSelector} from 'react-redux';
import { setCounterIncrement } from './store/slices/counterSlice';
import { GlobalStore } from 'redux-micro-frontend';
import store from './store/RootReducer';

const test = () => {
const counter=0;
const globalStore = GlobalStore.Get();

type CounterSelectors = Record<string, any>;

const counterSelectors: CounterSelectors = {
  getCount: (state:any) => state,
};

React.useEffect(() => {
globalStore.RegisterStore("CounterApp", store);
const unsubscribe = globalStore.SubscribeToGlobalState("CounterApp", globalStateChanged);
globalStore.AddSelectors("CounterApp",counterSelectors);

return (()=>{
  unsubscribe();
})

}, []);
return (
{counter}
)
}

export default test

// testing.tsx file

import { Button } from '@mui/material';
import { GlobalStore } from 'redux-micro-frontend';

const testing = () => {
const partnerState = GlobalStore.Get().SelectPartnerState('CounterApp','getCount');
const handleClick = () =>{
console.log("Hi",partnerState)
}
return (

testing

)
}

export default testing

in the testing.tsx file partnerState is setting to undefined