code: public Observable<VerifyResult> verifyFaceToPersonAsync(UUID faceId, String personGroupId, UUID personId) {
          return verifyFaceToPersonWithServiceResponseAsync(faceId, personGroupId, personId).map(new Func1<ServiceResponse<VerifyResult>, VerifyResult>() {
              @Override
              public VerifyResult call(ServiceResponse<VerifyResult> response) {
                  return response.body();
              }
          });
      }
docs: Verify whether two faces belong to a same person. Compares a face Id with a Person Id.
  
  @param faceId FaceId the face, comes from Face - Detect
  @param personGroupId Using existing personGroupId and personId for fast loading a specified person. personGroupId is created in Person Groups.Create.
  @param personId Specify a certain person in a person group. personId is created in Persons.Create.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the VerifyResult object