protected override IEnumerable<string> GetAuthorizedClaims()
{
if(this.ClaimsIdentity == null)
return null;
IEnumerable<string> authorizedClaims = this.ClaimsIdentity.Claims.Where(claim => claim.Type == this.ClaimsIdentity.RoleClaimType).Select(claim => claim.Value);
return authorizedClaims;
}