adder.accept(accumulator, SomeEnum.B);
    ImmutableSet<SomeEnum> set = collector.finisher().apply(accumulator);
    assertThat(set).containsExactly(SomeEnum.A, SomeEnum.B);

    // Subsequent manual manipulation of the accumulator must not affect the state of the built set
    adder.accept(accumulator, SomeEnum.C);
    assertThat(set).containsExactly(SomeEnum.A, SomeEnum.B);
  }

  @J2ktIncompatible

				writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAdminResourceInvalidArgument), r.URL)
				return
			}
		}

		if globalIAMSys.LDAPConfig.Enabled() {
			// We don't allow internal group manipulation in this API when LDAP
			// is enabled for now.
			err = errIAMActionNotAllowed
		} else {
			updatedAt, err = globalIAMSys.AddUsersToGroup(ctx, updReq.Group, updReq.Members)
		}
	}
	if err != nil {