code: public static DeleteUserRequest checkRequest(
  			final HttpServletRequest request,
  			final DeleteRequest deleteRequest,
  			final DeleteUserResponse deleteUserResponse) {
  		final Node user = checkUserIdentifier(request, deleteUserResponse);
  		if (user != null) {
  			return new DeleteUserRequest(deleteRequest.getType(), user);
  		}
  
  		return null;
  	}
docs: check a delete user request for validity concerning NSSP
  
  @param request
  Tomcat servlet request
  @param deleteRequest
  basic delete request object
  @param deleteUserResponse
  delete user response object
  @return delete user request object<br>
  <b>null</b> if the delete user request is invalid