code: public List<Person> list(String personGroupId, ListPersonGroupPersonsOptionalParameter listOptionalParameter) {
          return listWithServiceResponseAsync(personGroupId, listOptionalParameter).toBlocking().single().body();
      }
docs: List all persons in a person group, and retrieve person information (including personId, name, userData and persistedFaceIds of registered faces of the person).
  
  @param personGroupId Id referencing a particular person group.
  @param listOptionalParameter the object representing the optional parameters to be set before calling this API
  @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 List&lt;Person&gt; object if successful.