private boolean isEmailAddressRegistered(JiraClient client, String email) {
    for (RemoteUser user : client.searchUser(email)) {
      if (user.getEmail().equalsIgnoreCase(email)) {
        return true;
      }
    }

    return false;
  }
  private boolean isUsernameRegistered(JiraClient client, String username) {
    for (RemoteUser user : client.searchUser(username)) {
      if (user.getName().equalsIgnoreCase(username)) {
        return true;
      }
    }

    return false;
  }