code: public Observable<ServiceResponse<Void>> deleteFaceWithServiceResponseAsync(String personGroupId, UUID personId, UUID persistedFaceId) {
          if (this.client.azureRegion() == null) {
              throw new IllegalArgumentException("Parameter this.client.azureRegion() is required and cannot be null.");
          }
          if (personGroupId == null) {
              throw new IllegalArgumentException("Parameter personGroupId is required and cannot be null.");
          }
          if (personId == null) {
              throw new IllegalArgumentException("Parameter personId is required and cannot be null.");
          }
          if (persistedFaceId == null) {
              throw new IllegalArgumentException("Parameter persistedFaceId is required and cannot be null.");
          }
          String parameterizedHost = Joiner.on(", ").join("{AzureRegion}", this.client.azureRegion());
          return service.deleteFace(personGroupId, personId, persistedFaceId, this.client.acceptLanguage(), parameterizedHost, this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Void>>>() {
                  @Override
                  public Observable<ServiceResponse<Void>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<Void> clientResponse = deleteFaceDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Delete a face from a person. Relative image for the persisted face will also be deleted.
  
  @param personGroupId Id referencing a particular person group.
  @param personId Id referencing a particular person.
  @param persistedFaceId Id referencing a particular persistedFaceId of an existing face.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.