How to use the @igo2/core.IgoLanguageModule.forRoot function in @igo2/core

import { HttpClientModule } from '@angular/common/http';
import { MatCardModule, MatButtonModule } from '@angular/material';

import { IgoErrorModule, IgoLanguageModule } from '@igo2/core';

import { AppRequestComponent } from './request.component';
import { AppRequestRoutingModule } from './request-routing.module';

@NgModule({
  declarations: [AppRequestComponent],
  imports: [
    AppRequestRoutingModule,
    MatCardModule,
    MatButtonModule,
    HttpClientModule,
    IgoLanguageModule.forRoot(),
    IgoErrorModule.forRoot() // Only if you want register errors from http call in console
    // IgoLoggingModule.forRoot() // Only if you want register http calls in console
  ],
  exports: [AppRequestComponent]
})
export class AppRequestModule {}

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        RouterModule.forRoot([]),
        IgoLanguageModule.forRoot()
        // IgoAuthModule.forRoot()
      ],
      declarations: [PoiButtonComponent],
      providers: [[{ provide: APP_BASE_HREF, useValue: '/' }]]
    }).compileComponents();
  }));

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        RouterModule.forRoot([]),
        IgoLanguageModule.forRoot()
        // IgoAuthModule.forRoot()
      ],
      declarations: [],
      providers: [[{ provide: APP_BASE_HREF, useValue: '/' }]]
    }).compileComponents();
  }));

import { NgModule } from '@angular/core';
import { MatCardModule, MatButtonModule } from '@angular/material';

import { IgoLanguageModule } from '@igo2/core';

import { AppLanguageComponent } from './language.component';
import { AppLanguageRoutingModule } from './language-routing.module';

@NgModule({
  declarations: [AppLanguageComponent],
  imports: [
    AppLanguageRoutingModule,
    MatCardModule,
    MatButtonModule,
    IgoLanguageModule.forRoot()
  ],
  exports: [AppLanguageComponent]
})
export class AppLanguageModule {}