How to Use custom ionic cordova Plugin in ionic 5

Question

I have created a custom cordova plugin and it is been installed in my ionic5 app while doing ionic plugin list but while trying to use the plugin by creating Ionic wrapper class and using @Plugin and @Cordova,

import { Plugin, Cordova, CordovaProperty, CordovaInstance, IonicNativePlugin } from '@ionic-native/core';
@Plugin({
  pluginName: "mathcalculator",
  plugin: "cordova-plugin-mathcalculator",
  pluginRef: "MathCalculator",
  repo: 'https://github.com/deepak1003/mathCalculato.git',
  platforms: ['Android']
})
@Injectable({
  providedIn: 'root'
})
export class MathService {


  @Cordova()
  add(arg1: any): Promise<String> {
    return;
  }
}```

**it is giving error**
export 'Cordova' was not found in '@ionic-native/core'
export 'Plugin' was not found in '@ionic-native/core'