code: public Person get(String personGroupId, UUID personId) {
          return getWithServiceResponseAsync(personGroupId, personId).toBlocking().single().body();
      }
docs: Retrieve a person's information, including registered persisted faces, name and userData.
  
  @param personGroupId Id referencing a particular person group.
  @param personId Id referencing a particular person.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws APIErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the Person object if successful.