Calling Power BI API to get tiles in group

getTilesInGroup.ts

public getTilesInGroup(groupId: string, dashboardKey: string){
  const headers = new HttpHeaders({
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${this._context.getCachedToken(environment.powerBIEndpoint)}`
  });// this._context is the ADAL AuthenticationContext object
  return this.http.get(`https://api.powerbi.com/v1.0/myorg/groups/${groupId}/dashboards/${dashboardKey}/tiles`,  { headers: headers });
}