code: public Observable<ServiceResponse<Void>> updateWithServiceResponseAsync(String personGroupId, UpdatePersonGroupsOptionalParameter updateOptionalParameter) {
          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.");
          }
          final String name = updateOptionalParameter != null ? updateOptionalParameter.name() : null;
          final String userData = updateOptionalParameter != null ? updateOptionalParameter.userData() : null;
  
          return updateWithServiceResponseAsync(personGroupId, name, userData);
      }
docs: Update an existing person group's display name and userData. The properties which does not appear in request body will not be updated.
  
  @param personGroupId Id referencing a particular person group.
  @param updateOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.