docs: public static FormValidation validateEmails(String emails) {
          if (!Strings.isNullOrEmpty(emails)) {
              String[] recipients = StringUtils.split(emails, " ");
              for (String email : recipients) {
                  FormValidation validation = validateInternetAddress(email);
                  if (validation != FormValidation.ok()) {
                      return validation;
                  }
              }
          }
          return FormValidation.ok();
      }