code: public Observable<PersistedFace> addPersonFaceFromUrlAsync(String personGroupId, UUID personId, String url, AddPersonFaceFromUrlOptionalParameter addPersonFaceFromUrlOptionalParameter) {
          return addPersonFaceFromUrlWithServiceResponseAsync(personGroupId, personId, url, addPersonFaceFromUrlOptionalParameter).map(new Func1<ServiceResponse<PersistedFace>, PersistedFace>() {
              @Override
              public PersistedFace call(ServiceResponse<PersistedFace> response) {
                  return response.body();
              }
          });
      }
docs: Add a representative face to a person for identification. The input face is specified as an image with a targetFace rectangle.
  
  @param personGroupId Id referencing a particular person group.
  @param personId Id referencing a particular person.
  @param url Publicly reachable URL of an image
  @param addPersonFaceFromUrlOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PersistedFace object